pregnant on the pill?

it’s 2 days until my withdrawal bleed after skipping my period for 4 months with my pill. 2 weeks ago i finally finished a 12 day long episode of black/dark brown breakthrough bleeding (pic is tmi i’m sorry). i take the pill perfectly, and have been for almost a year now, but i’m still scared. i normally only skip 3 months and i’ve been doing that for a while so i didn’t think skipping a 4th month would cause this much of a problem. ive heard that this is just my uterus “cleaning itself out” but it was soooo heavy. was it my uterus trying to make room for a baby? i don’t even know if that makes sense, but i’m scared. the bleeding started off as light brown / pinkish, so implantation bleeding was automatically my first worry. then it turned into this heavy, dark brown bleeding. i was still taking my active pills throughout this whole time so i was worried. it lasted a total of 12 days, some days i could see hints of red in the blood, but it was mostly very dark brown and black. i totally cannot have a baby right now. i’m only 16. when me and my boyfriend had sex the last time, on june 5th, we didn’t use a condom but he pulled out (i think). i take my pill perfectly and with no other medications, but for some reason i’m still paranoid. it’s now almost a month after we had sex, and about 2 weeks since the breakthrough bleeding. recently i’ve been having light nausea (when i think about it) and my nipples seem to be perkier (but they don’t really hurt). could it be a hormone imbalance from skipping the placebos for so long? is it because i begin my placebo pills in 2 days? am i pregnant? HELP! i really don’t want to get a test because if i actually am pregnant, i have no idea what i would do. i swear i’ve been feeling my lower abdomen “stretching out” or “pulling.” should i just wait and see if i get my period during the placebos? i see no reason why my birth control would’ve failed, but for some reason i just don’t trust it. it may be because i only recently started becoming sexually active and i’m still very new to the whole “trusting a pill” thing. whatever it is... i just want to know what’s wrong with me. do you ladies think i should test if i miss my period this upcoming week? let me know! here’s the pic.. it’s so gross i’m so sorry.