Could I be pregnant?

Hi ladies I need help 😭. So my boyfriend and I had sex multiple days, several times a day, before and after my fertile window of Aug 8-13. He finished inside of me each time. During the fertile window we practiced withdrawal method. So then August 15 I had an episode of diarrhea- very random and it resolved within a day & a half. But ever since then I’ve been very gassy and have been experiencing gas cramps. Moving ahead to August 20 (a week before my period is due according to glow) I had period like cramping that was on and off all day and this continued until the 21st. Since the diarrhea episode I’ve been feeling weird. On the 25th I took a pregnancy test and it was negative. I have been experiencing breast tenderness since the 25th which is kinda unusual for me (as a PMS). Now my period is just 2 days late which my period has been late before but recently it’s been on time or early). Also been experiencing fatigue (napping after work and inbetween classes), increased appetite (kinda a usual PMS thing for me) and slightly more urination.

Please help with thoughts or suggestions.