i know its long but please help me im freaking out

so I'm 17 was on the depo shot for a year. after being off of it for 3-4 months I started noticing weird things. in the past few months I have gained 15 pounds (which I'm not complaining. I needed the weight gain. originally like 98-100 and now I'm 112) but I noticed my boobs have been really sore on the sides. well I started feeling around in my boobs and I feel a lump or a knot. I haven't had an actual normal period. after I was supposed to get my last shot and when I didn't I started bleeding for two weeks straight. it stopped and I would spot every few days. well now it's only when I wake up in the mornings with blood running down my legs if I don't wear a pad to sleep in (I don't know when I'll start bleeding it happens every few days and I am TIRED of wasting pads waking up not bleeding. but I thought I might've been pregnant CD50 took a test and it's negative every time. I get really sharp pains in my stomach every few hours and sometimes they are so bad I want to cry. some have actually had me in tears not wanting to move. so I finally get the chance to go see my Dr and she setting up appointments for me to have a breast and pelvic ultrasound and I'm really freaking out and I have to go get blood drawn Monday and I'm really scared and paranoid. what if there's something wrong with me. and every time I think about it I just cry because I don't want my chance of having a baby taken from me when I was forced to get on birth control.