I find it disheartening that the current thought is that a “B” is a bad grade. It isn’t. Not everyone is going to get an A and “back in the day” when it wasn’t uncommon to get a C in a college class. I guess this is what grade inflation has done.
Everyone is nervous about starting college. They are nervous if they can do the work, nervous about making friends, and nervous to be living away from home. Just do your best, keep a good attitude and keep putting one foot in front of the other. You can do it. Try to enjoy the experience and don’t think too far ahead. Just deal with one thing at a time.
I also happen to think that loneliness is a feeling that is common among people in their 20s and maybe even 30s (and beyond) who are living on their own. It’s a big change to be self-sufficient. IMHO, being alone is something that has to be learned and some never learn it. Hang in there - growing up is hard but you can do it.