HELP im worried

Hello I am 21 years old and I am in a relationship I have a question first let me tell you my story so you understand my situation. I started my period at 12 yrs old like most girls well around 14 my period just stopped and never came back well when I turned 18 I got on birth control to see if it would jump start it back and it did every month it would come for 7 or 8 days but it wasnt regular it was irregular well then I switched to depo because I would forget to take the bc pill well that stopped my period for 3 months and then gave it to me for almost 3 weeks straight. Well then about a year I stopped taking birth control completely since I stopped having sex. Well then I got with my boyfriend 8 months ago and I am still not on birth control but my period is regular well sometimes it comes a week early but I still get it and we use protection.well around my suspected ovulation we had sex and we use condoms and well when he went to pull out the condom got stuck inside of me and now im almost a week late on my period is it possible that I could be pregnant please help me and tell me what the best affordable pregnancy test would be im really scared . Help I need advice.