Hi there Emily, first of all I would like to say that I do understand exactly how you're feeling right, I used to - and still ocassionally - grapple with the thought of Hell. It's very difficult when we think of our loved ones, and their eternal fate, because of course we love them and care about what's going to happen to them. So you have my empathy on this heartfelt question.
If I may, I'd like to guide you step by step, in the way you can approach these questions, and approach the whole topic of Heaven and Hell.
First of let's look at Psalm 7:11: "God is a righteous judge, and a God who feels indignation every day." Looking at this verse we can see that God is always fair, and that he feels indignation every day because of the many sins against him. God is holy, and this means any sin is an abomination to him. So the fact that we're here and alive, shows just how much he loves us.
Bearing this in mind, it may be easy to raise the question: If God loves us, why does he punish unblievers in Hell? It may seem that it's a cruel fate that a loving God would be incapable of right?
Let's take a look at this scripture in Isaiah: "For as the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts." --Isaiah 55:9
If you think about what God is saying in this scripture above, it brings the realisation that sometimes we forget that God is the creator of everything, so of course he will have a higher sense of Justice, than us, also other things such as a higher sense of Love. So if we say "A loving God wouldn't send someone to hell for eternity", we bring God down to our level of Justice and Intellect and of course, looking at Isiah, we can see that his ways are to much greater than our own, so his decisions will always be the right ones.
It's also easy to get so caught up in the negativity of Hell we miss just how much God loves us! Let's have a look at some more scripture and see what we can learn about God's love for us.
In Psalm 7:11 we see that God is angry at us sinners every day! However, through his love, mercy and grace he sent his only son to die on the cross and bear the wrath of God which was meant to be for us. This is the sort of love unimaginable, isn't it so wonderful? Here's a very well known piece of scripture I am sure you are familiar with: "For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life." --John 3:16
Here is another precious verse from the bible: "Christ redeemed us from the curse of the law by becoming a curse for us—for it is written, “Cursed is everyone who is hanged on a tree”-- Galations 3:13
So we know that God hates sin and those who Sin... yet he did the above for us? Christ became a curse for us? That is what we should focus on when it comes to Hell. Just focus on the cross totally. Begin there.
As for finding peace and comfort, I pray to the Lord, and also read the bible, it's his word and his word is amazing! The word is required for the transformation of our lives and gives life! "Truly, truly, I say to you, whoever hears my word and believes him who sent me has eternal life. He does not come into judgment, but has passed from death to life"-- John 5:24
"Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come"-- 2 Corinthians 5:17
The above verse tells us that when we're save through Christ we become a new creation/creature! This is not instantaneous, however, God will not let you stray far from the right path. So seek him out, pray to him sincerely. Read his word as much as you can and he will fill you with the Holy Spirit. Don't worry too much, we cannot be perfect, and we certainly cannot fight sin by ourselves. We need God to do that, we need to have faith in him to help us, and give us strength. Here is another encouraging piece of scripture: "You foolish Galatians, who has bewitched you, before whose eyes Jesus Christ was publicly portrayed as crucified? [SUP]2 [/SUP]This is the only thing I want to find out from you: did you receive the Spirit by the works of the Law, or by hearing with faith? [SUP]3 [/SUP]Are you so foolish? Having begun by the Spirit, are you nowbeing perfected by the flesh?"--Galation 3:1-3
What Paul is saying the scipture above is that, is foolish to try and become saved through human efforts (works), this is only possible through salvation, and it begins with the spirit! So focus on Jesus Christ and the rest will follow! To be saved focus on him and loving him.
With regards to your questions on catholics, it's not an easy questions to anwer, because everyone is different you see? I don't think catholicism is correct, however it's wrong to to condemn someone because of their denomination/church. Only Jesus can see into someone heart! Don't worry, find comfort in Jesus, he loves you, and cares about you, spend some time with him reading his word.
Finally, you have nothing to be afraid of! I hope you can see this from what have written here, I am sure it's a bit jumbled and confusing. It's great news that you are concerned about your own and others people's eternal fate, God know's you're worried and scared, throw your anxieties on to him, and he will help you. I really hope I have helped, if you have any other questions or need some things clarified feel free to PM me! I'll just drop off a beautiful verse at the bottom for you to read and think about! =D
"And a lawyer stood up and put Him to the test, saying, “Teacher, what shall I do to inherit eternal life?” And He said to him, “What is written in the Law? How does it read to you?” And he answered, “YOU SHALL LOVE THE LORD YOUR GOD WITH ALL YOUR HEART, AND WITH ALL YOUR SOUL, AND WITH ALL YOUR STRENGTH, AND WITH ALL YOUR MIND; AND YOUR NEIGHBOR AS YOURSELF.”"-- Luke 10:25-27