Serious question

I was in the implant for 3 months (October- December) and the day it was removed I was put on depo. Was due for my next shot on the 1-6 of march. Been on and off BC since 2014 but decided December was the last time I'm on birth control. I haven't gotten my period yet and have had (alot) of unprotected sex with hubby before my shot was due and after and still I dont want to get the shot and I've had spotting on and off since the 15 and it's only when I wipe its pink some times and it's in the discharge. I want to be pregnant and on friday I took a test and was negative. is there any possibility that I could be pregnant at all. I've never gotten pregnant before even on my BC "breaks" or even on accident I really want to know for my sake and if I could possibly be pregnant for my babies sake.