First off I'm sorry that you're feeling so lost. This isn't a quick fix problem and this might be hard to hear but this is why so many marriages fail when you marry so young. College is typically a time where you learn and grow into an adult, it's a period of change and that's what your wife is doing, the problem is that she's changing and growing away from you. The fact is that she is missing out on a lot of milestones most early twenty year olds experience, both of you are.

I think a big part of your problem is that you say that she's your entire world, she can't be your entire world that is too much for anyone to handle. You need to find other means of support.

If you truly want your marriage to work I think you both need to go into counseling but be prepared to separate. She might need to spend some time alone.