Hi. In Need Of Help. I Had Sex A Few

Hi. In need of help. I had sex a few months ago. (It was protected) i had received my depo provero shot a few days prior. I had very heavy bleeding which I assumed was my period a couple weeks later. The next month I had spotting at the time of my period & the month after was the same. This month no period at all and tender breasts. (I didn't get my next depo shot) I also started an antidepressant in the last couple of months. is it possible that the missed period is due to coming off the depo or the antidepressant as well as stress. Or does it sound more like pregnancy?