My boyfriend came in me after being on DEPO for just one week am i pregnant? URGENT.?

i got the depo provera shot on march 13th but when i got it i wasnt on my menstrual cycle like your suppose to be when you get it,anyway my boyfriend and i had unprotected sex on the 21st,28th,the 1st of april, the 7th, 8th and 10th(today)and i just found out that im ovulating this week which i guess means that i am even more fertile?. anyway my boyfriend cummed everytime we did it unprotected and we kept going even after he did. the reason me and him have been having unprotected sex is because im pretty sure im pregnant anyway because about a week ago i took two tests,1 postive(taken in the morning)and one negative. and i've been having all the early pregnancy symptoms. It hadn't even been a week after the shot that me and him had unprotected sex more than once and im 17years old and very fertile. It seems like nobody at plan parenthood can give me a answer so i came here, and also just today i started spotting small amounts of brown discharge i think is blood. So here's my questions:
Can i be pregnant when i didnt use protection after only being on the shot for one week?
Can i still get pregnant even though the shot is in effect if i continue to have unprotected sex since im really young and fertile?
How soon can i get a 100% accurate test?
Can i stop taking DEPO before the 3months is up?
Why am i bleeding/having brown discharge if i am pregnant?
So those are my questions. I DO NOT want to be lectured i understand i was stupid but right now i just need truthful educated answers. I will take full responsibility for my mistake but i will NOT have a abortion if i am and i dont believe in the plan b pill so please dont offer that. Thank you very much.