help pleasee

so I’m getting worried because I’ve felt full of air like really gasy, felt slightly sick in the morning and been so tired. I didn’t think there was anything to worry about because me and boyfriend didn’t really have sex like it didn’t go in fully and he came already when I tossed him off first but I’ve read things that say I don’t actually have to fully have sex to get pregnant so now I’m working I’m due on my period next week and I’ve got exams at the minute aswell so I thought maybe that might be why I’ve been feeling so tired but I can’t help worrying because I’m 16 I don’t know what to do-just need advice please x