Pregnant? Long but please read.

I’m 15 years old. I’m currently on my 2nd depo shot. I was bleeding for about 4 weeks but it immediately stopped once i got the second shot. The day after i got my 2nd depo shot, I did but didn’t have sex? his penis went in me like 2 times but i told him to stop because it hurt. we did use a condom and i feel safe because of the shot, however that was 3 weeks ago. this past week i have been having white discharge which is normally ovulation time for me but my stomach has been hurting a lot and i have been having severe cramps. I was wondering if it is possible that i could be pregnant but i feel positive that not even precum got on the condom or even in me but i researched and it says pregnancy symptoms are similar to period symptoms. My period normally comes around the 12th but it is the 28th.

Also, I’m thinking that since my period was longer because of the shots effect, I’m thinking that my period is getting used to that time if that makes sense? Every 4 weeks, (a month) my period comes and its been 3 weeks since i last bled so im thinking that my body is adjusting itself to that time rather than starting around the 12th like it used to? Am I correct or is something else wrong?

What should I do?

Should I tell my mom I ‘had sex’?

Update :

I looked up my symptoms and i keep coming back with results saying i have “ibs” or irritable bowel syndrome and it sounds more accurate lmao so im relaxing right now but im still scared. However I’ve been having stomach pain for about a week but I’ve only been having trouble using the bathroom for about 2 days so im wondering if it will go away and i will stop worrying