If you get involved with some form of helping others, with a God-based group, and actually SEE how Jesus works in peoples' lives, it will "refresh" your memory of just what "living in Christ" has to offer...
You also have to remember that much of what we believe is simply on faith. Sure, we have historical documents, and records, but very much of what Jesus brought simply requires faith.... Don't expect to find "proof" of Jesus through science, or your own intelligence. That's not where He is... You need to become simple, and child-like again, and believe what you see, and experience. .....ask me how I know.
I'm not saying we should become stupid... not at all. We just need to realize that the principles Jesus taught have lasted, unchanged for 2000 years. What science "knows" and has "discovered" changes almost daily.... and, it's "new" discoveries almost always point back to God, whether they admit it, or not.
I suggest you read some of Lee Strobel's books... he's written several... "the Case for Christ", "the Case for a Creator", etc... He was an avowed atheist, and investigative reporter, whose wife became saved. He then set out to investigate and "prove" Christianity to be false, based on myths. Instead, he found Jesus
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And, CS Lewis' book, "Mere Christianity" ... which I'm finally reading for the first time (Thanks Willie!)
If you truly want to come back to Jesus, He's waiting with open arms... you're in my prayers.