my situation is only sort of similar to yours. i've lived in my home state for about 11 years now. and i've met a lot of people from going to schools in five different cities, but i'm actually friends with only some of them. before i started pharmacy school, i knew 2 (out of 120 total) people in my class. there was no one from my undergrad college and no one from my high school. and also no one from my middle school or elementary school.
i had to make an effort to try to meet people and talk to them every day. i joined some clubs and from that met even more people in my class. i ended up running for an officer position and got elected as a liaison for the entire p1 class since more than half of my class voted for me 🙂
but, i will say though, that it takes time. and you won't automatically know people just because time passes. if you decide one day to take five minutes out of your day to go talk to that girl who sits in front of you, you two might end up talking to each other more from being in class. and then she might introduce you to her friends, and then you'll know more people, and so on. so you don't always have to take time every single day to talk to people. they understand that you're busy. but if you just take a minute out of your day to talk to them, it will be a good thing in the long run.
as for studying, i studied a lot more than i probably did back in college, and i still do. and on my first test, i also made a B, but i thought it was difficult. and then i started to wonder why i was so worried about it. from then on, i started realizing that i could take time to hang out with friends and go downtown sometimes and still improve my grades and studying habits.
i know it seems difficult right now, but you'll find what works for you. and when you do, school will be a bit easier to get used to.