Chances of getting pregnant?!?

Okay so I’ll get straight to the point, I’m on skyla IUD for about a year now and I started my relationship like 4 months after getting it inserted (no partners before). My boyfriend cums inside me all the time 🤷🏽‍♀️ and lately he noticed that my string is getting too long and I’m worried it might be coming out. Would the birth control not work if it feels like it’s coming out and he’s still ejaculating inside me? Or am I just crazy. My mood swings have been really bad and I’m really tired, was vomitting and craving food (even tho Im always craving food😂), could there be a chance that I’m pregnant?

***** I made a doctors appointment to get it cut already btw