Pregnancy tests coming back negative but...?

I'm so confused. I was on the depo shot for five years and I decided to switch to the pill. I did as the dr. said when I did but now I'm afraid I could be pregnant. I have taken seven home preg tests over the past week all negative. I've been having problems with my stomach and two people I know suggested I might be pregnant when I told them about it. I go from constipated to diarreah to nausea to dizziness. I'm on my third pack of pills so it's been awhile since I think the chances were higher when I switched. Now I was minding my own business having dinner and watching tv and I felt like I was about to cry for no good reason nothing on tv could have prompted it I'm so confused that has never happened to me ever. It was really creepy. I had a period last month for the first time in five years and it was at the right time in my bc pack for that to happen so I don't think it was implantation bleeding I took another preg test about 15 min ago negative. Kicker in this is that I lost my health insurance I just aged out the day I saw the gyno about switching so now I have no doctors I can turn to. I'm so worried and confused I'm working two jobs and just started a cl at my comm college I have no time to go to family planning when they're open I'm wondering if I should just go to the er and apply for charity care. Any advice and opinions on if I could be pregnant would be greatly appreciated.