I really need an answer here. Please tell me what you think.

I used the pull-out method on October 11th, the day after my period ended and a day or two before I ovulate (Yes, I know, not very smart, please spare me the lecture) About four days after that I got a mini-period, not spotting but not heavy, and it lasted no more than 24-36 hours. I have never had something like that before, but I still wasn't concerned about pregnancy. Then less than a week later I started getting really bad cramps, usually when I was waiting in the heat at the bus stop, it'd just be this deep pain around my uterus and I'd almost double over it hurt so bad. That quit after about a week, and then on November 3rd, when my period (Due October 28th) was six days late they took a urine test, which came out negative, and I got my first ever Depo shot, at the free clinic. Since then I didn't give it much thought, but I hear it's pretty rare that your period stops immediately on Depo, usually you bleed a lot for a long time when you first get it? Anyway my period is twenty one days late and I'm due tomorrow. Before I got my Depo shot I was also experiencing headaches, which cleared up a bit about two days before and five days after my shot, and then returned in extreme force and have been going on for about a week and a half now, I'm talking about constant and very painful headaches. Also, my cramps have returned, not so bad but still. I'm feeling a bit nauseous, and today I mixed a lot of really weird foods at lunch, everyone was looking at my tray like Uhmm you're going to eat that..? I've also been getting some pretty bad mood swings since before the Depo but I don't know if that's just stress or whatever, I have some anxiety issues and such.. I'm getting cold a LOT during classes, I always have to ask them to turn the heat up, even if it's not cold. My hands and feet are always freezing. My lower back is hurting. My calves are hurting like I've recently been walking a lot even though I haven't, and when I flex my feet all the way up my shins are achy. My pelvis muscles are a bit sore as well. I can see the veins in my boobs but I don't know if I could do that before or what... And apparently my boobs got a bit bigger? I've only been on the shot for about two weeks. Also I've got some extreme fatigue and concentration issues, the fatigue started before I got the shot but I'm not sure about my trouble concentrating. Does this sound like side effects from the shot or pregnancy? I'm going to visit my family in another state tomorrow for the whole of Thanksgiving break tomorrow so I can't even think about making an appointment until then, and I'd have some issues getting around my parental unit for an appointment even when I do get back. I can't afford the five dollar pregnancy tests and the dollar store is too far away. What does this sound like to you? Thank you so much for your opinion.

Oh, and because I have asked this before, would you please take time to remember that most of this started before I got my shot? I just really need answers and everyone always thinks I got my shot before, but I got it after this little mishap, and my period was about 5-6 days late, and they urine tested (negative) and I have never gotten the shot before this. Thank you