HELPPPPPP. Am I going crazy?

I’m 18. I had sex with a condom, no rip or tear. Idk why I did this but after he climaxed I kept riding for a few minutes so I could finish . Then I got off. He took his condom of and that was it . This happened Sunday it’s now Saturday and ive had a weird feeling in my stomach. Am I just paranoid and my body is playing jokes on me ? Could I really be pregnant. I’m supposed to get my period in a week. What should I do lol . I feel constantly like gasy/bloated