I need answers

So I’m 17 and I’m in a relationship with my boyfriend for over a year now and I have a situation. So my period is more than 2 weeks past due and I’ve been very nauseous and dizzy for a while now. I don’t know if I should take a pregnancy test because the last time we had sex was over two months ago. I was told I may either be pregnant, have a tape worm, or maybe the stomach virus but I’m really scared. My mom knows that there’s a possibility and so does my boyfriend. I haven’t gotten any fatter but I’m naturally very skinny. I’ve always been skinny and thin and very low in weight. I just want the blunt truth. Please tell me what it might possibly be and if I should take a test 😔