I'm so worried idk what to do😔

So I've been checking the calendar it's been 5 weeks since I haven't gotten my period I'm very worried because I should've gotten it but I didn't. I don't think I can be pregnant every time me and my boyfriend have sex he always uses protection pulls out before cumming. Any advice can it be possible that I can be pregnant cause my boyfriend says it's impossible. What can I do?😏