Guy problems

I really like this guy. He's 23 in medical school. I'm 22 and starting medical school in the fall. We met on tinder and started hanging out. I started to gain feelings for him. I really like him and actually felt like he's the right person. When we first started talking, I used to go see all the time every time of the night but as of lately I can't see him when he wants me to because of family problems. When I explain to him I can't make it he always says I'm standing him up. It's really frustrating. Two nights ago I got off work and went to see him and ended up sleeping over(first time). I thought we had a great time. I left and texted him saying I had a great time but he never texted back. Yesterday I wrote him on Instagram and he wrote back and told me to "not worry about him no more". I don't know what to do or say and it made me feel really bad because I'm thinking I'm not good enough for anybody. It's always the same thing with every guy I talk to. Help please