Am i pregnant ?

hey there ,

well i have many questions . i really dont know what to do . Help Please !

so my period is irregular , it comes any day it wants but every month , maybe some times 2 or 3 days later of the next month .

buut anyways , i got my period July 20 (First day ) and it finished July 25 , i had unprotected sex on July 27 , July 30 & August 30 .

On August 6 , i had that brownish discharge , & i was telling my self what is this ? ive never had this before . ive had but it was way less than this time . i felt wet down there and i went to check , i wiped my self and then thats when i had felt it , i thought it was period but it wasnt . i started to think to myself am i pregnant ? all these ideas came to my head but then i thought , i should assume things . so that next following week i had un-protected sex On August 17 . the next week on monday August 20 , i expect my period but really wasnt surprise if it didnt come since am irregular . i had taken a pregnancy test that same week it came out negative , i also assume it was to early to test . so i told myself that i was gonna wait until the end of the month to test again . so its been like 2 weeks since ive had any type of sexual relationship with my partner . but i think its wierd because i havent had the urge to do so .i think it was thrusday or wednesday of last week when i tested again & it came out negative again . my period has been missing for more than a month ! i dont know whats happening . i havent had any syptoms at all . ive just been noticing that when i dont sit up striaght for like 2 or3 mintues , my back starts hurting . and when i have to pee , i cant hold it for every long because i feel really uncomfortable & feel like my bladder is gonna explode ! i hope this is enough info , please help . i wanna know what you guys think is going on

Thankkkkkkkks ,