I relate to so much of what you've said here! It can really hurt to see some distance develop between friendships. I think that - seeing as college is so different to high school - you can expect that friendships in general take a bit of a hit seeing as people move to different colleges. That is understandable, and petty arguments may be an outlet for this distance, so don't worry too much about that. You're in college! There is such a variety of different people at college, and I relate to you in terms of being a bit shy in the beginning. I recommend that you hang out in areas where you are already comfortable (whether that's a library, a coffee shop, a park, a club etc) and try to network from there. Ask for a phone number from a classmate to double-check work, because it is an opportunity to speak over the phone and it may feel a little bit less uncomfortable. If you enjoy parties, attend those where students outside college go. Perhaps consider a part-time job at a coffee shop or something similar, and you will almost certainly make friends with the people you work with!
Hope this helps! Xx