Matthew 19:10-12 (NIV)
10 The disciples said to him, “If this is the situation between a husband and wife, it is better not to marry.”
11 Jesus replied, “Not everyone can accept this word, but only those to whom it has been given.12 For there are eunuchs who were born that way, and there are eunuchs who have been made eunuchs by others—and there are those who choose to live like eunuchs for the sake of the kingdom of heaven. The one who can accept this should accept it.”
The above shows some a born single and it's not just God's calling on them, they happy and content to be that way. So on the other hand despite the loneliness or yearning to be married and/or have a family choose instead to devote themselves to working to bring God's Kingdom, and God empowers those for that. And despite the things have to give up, they are compensated by God a deeper relationship with Him, and are given as promised a new family of the church that like Paul (this applies to first type above as well) and spiritual children which to fellowship and be apart of, as well as being used mightily by God.
And then there is the last, those who are made eunuchs by others, this of course could be meant literally but I think it always applies to those who for whatever reason are not able to find that one person we can spend our lives with in marriage (for all sorts of complicated reasons), even though they desire it, and don't feel particularly either called (or choose) singleness. Sometimes singleness is thrust on us, for a season, or maybe even all the time before the resurrection. I probably belong somewhat in this last group, but no matter what, even here through all that hurt and loneliness God does still work, and promises not that not hard (because I think many here could say that would be a lie) but that He is there, and I hope the church should be there as a family, and He will be in us, and work something beautiful (just as with the first two) in and through it, both for us and for the church and world. For all that we have lost we will be given new families and the eternal resurrection life of the age to come.
Also I would say the church, just as marriage can function as a picture of Christ and His love for His Church, and family can communicate the Father's love for His children, the single life is also just a vital a picture of our (and Christians and the church as a whole) total dependence on God for our support, or sustenance, comfort and love. That in everything He is the Source for all our needs, and is Our inheritance and portion, and models to the Church God's love for us and individual people, unique human beings which are to reflect Him into the Church and world in our unique way, showing His love in our unique way. the Church needs to value not just singles individual, but it needs to value the godly single life lived openly in the Church community, as the model of just how we all are, single or not, dependant on God, and as a model that shows just how important each person is individually to God, and are vitally important individually to the church (only they can do the unique tasks for the Kingdom, and be that unique part of the Body, and the single can be a model that can bring this home.
So yes, I feel lonely as I've said elsewhere, I feel it more as I get older, and it's hard sometimes, particularly reflecting that as much as I would like to be married and not be alone, that might not be the case, however as I reflect on the above, I have hope, and I know God is with me, as He is with all of you, and I know even in this He will do something beautiful through both our lives as singles and as married people in the community of the church.