Please answer 😕

So according to this app my period is supposed to come today. I was using the restroom around 6pm and I was bleeding so I believed I had started my period. I went back about an hour or two later to use the restroom again and I stopped bleeding. There's no bloody discharge just clear as if I was never bleeding. I have also been experiencing render breasts, back aches, headaches, constipation, abdominal cramps and stomach aches. The last time I had sex with my boyfriend was Valentines Day and although he used a condom it didn't start off that way. Valentine's Day was that 12-13 day of my cycle. I am worried yet excited to know if I may be pregnant.