Pregnant? Miscarriage? Help!

Okay. So this is kind of long, so I apologize in advance.. 
Around November I had my Nexplanon put in. The first period I had was a little longer than normal but since then has been completely regular. My boyfriend and I have been together almost 8 months, and we rarely use condoms. Everything was normal, but now I haven't had a period since my last one ended at the end of April. I didn't think much of it except for it being the Nexplanon, that is until I started experiencing pregnancy symptoms mid-May. I took about 3 tests, but they were all negative, so I started to do research. After many hours of searching through Google (I know, it's not always credible), I found that in some cases, the Nexplanon gives off so many hormones that the pregnancy test will automatically go to negative. I would just go to my gyno, but I have recently had my insurance cancelled thanks to my sperm-donor of a father, so I can't afford to go. Just recently my symptoms have worsened. My cramps are so terrible, and I've had dark brown discharge spotting. So can anyone help me..?