Beta, this is somewhat familiar; I'm older now but at your age felt totally alone. I wish I'd had the friendship/mom base you mention, but alas such was not the case. But I can relate to the "shame of having emotions" well, even with some you think might understand. The 'getting through' to them about what you truly feel is discouraging, as you've indicated.
In my case, the discouragement caused me to isolate further--part of me needed that as it felt safer that way; but other issues like 'dissociation' snowballed to where the original 'good' sense of escaping my pain resulted in some habits and patterns I didn't recognize were even present.
As an 'older' person, it can even be trickier as the habits settle in, but if you stick with listening to your 'best' friend--YOU--that could be what's most needed; not just now but as a general principle. So by your taking time off to consider a little bit where you're at seems very apropos; interestingly, many don't or can't take that time for themselves; and that can feel worse.
Visiting here fits well into your search to discover what's going on inside that you can't share with friends or mom, for the reasons you indicate. This is like landing in a spot with fellow travelers who know the struggles firsthand. There aren't easy or apparent 'answers' all the time, but it might be easier to relate those feelings you can't get out otherwise. And there doesn't seem to be a 'perfect' way, either; which means risking more discouragement, but we're still here, still trying, however our path unfolds.
You didn't mention if you have a therapist. Perhaps one might available through college? My experience with t's is mixed, but they did (sometimes) provide one outlet when I had no other--one mistake is in college I got into the solo trek exclusively, and didn't trust any outsider, including t's, as an option for help. I was so discouraged I could trust no one.
So here's hoping you do feel safer here, in whatever way you choose to use these resources--by reading, contributing, or just realizing that yes, you're not alone with this.