Am I Possibly Pregnant?

i’m 18 and have been TTC for 9 months. here’s some information about me:

i have very irregular cycles but my average is 34 days. was ejaculated in during my fertile window while i was on top of my partner (don’t know if that matters or not). i’m supposed to test in 3 days but i’ve gotta negative tests the past few days. currently, i’m on cycle day 31.

i’m currently experiencing brown spotting but not enough to show up on my underwear or a panty liner. i’ve had cramps but sometimes it’s on the left side, and it feels like my ovary is throbbing (which i know is impossible... right?) i sometimes get lower back pains as well. i haven’t had any other symptoms and i’m feeling slightly discouraged.

i’m turning 19 next month and i’m just very frustrated it’s taken me this long to ttc. i’ve had friends accidentally get pregnant in high school just one time of having sex with just doing the pullout method.

would i still have a chance at a positive pregnancy test after 3 days? is brown spotting a sign of pregnancy?