I keep getting ghosted by girls I meet at the club/bars

Hey everyone, I’m really struggling with this. I’ve [18M] only been out 5 times since moving to the city and met 4 girls I really connected with, I exchanged instagrams with them and they all asked me to message them as they were leaving the venue. I know these aren’t the types of places you’d ideally want to meet someone, but why do I get ghosted every time?

What should I be saying? I met this girl [18F] last night and we go to the same uni, take the same course, and have several common interests. We talked for a good 2 hours and made out for quite some time. I really don’t want to fuck this one up. Previously I’ve said how I had a lot of fun with them and would like to hang out again, but I always get ghosted. Should I be less direct? Is there something i should be saying instead?

TLDR: I keep getting ghosted by girls I meet. Just met another and need advice on how to message her next day.