Is it possible I had a miscarriage? PLEASE HELP!

So, first of all, I am on birth control and I'm pretty good about taking it on time with occasional slip ups. Other than that my boyfriend and I don't use any other type of protection. The last period I had, according to my boyfriend since I can't even remember the last one, was in December. I always took the 7 day break but nothing came. The first time I missed it I took a homepregnancy test that came out negative and figured I was thrown off because of my pills. But even after the negative test, my boyfriend and I were so positive I was in fact pregnant. I experienced symptoms and we both had such a strong feeling. I knew something was different it was almost like a fantom pregnancy. In the following months I'd have minor cramping when it came time for my period but it would pass after one or two days. Then about a week ago, while still on my pills, I started spotting with no warnings like slight cramping like I normally get and it was weird colored and chunky. This has happened before and I haven't had a period in so long I figured it was fine. I spoke to an advice nurse and she recommended taking another home pregnancy before coming it. I took one I believe yesterday or the day before and again it was negative, but kind of a light line instead of a darker one like before (same exact brand of test) if that makes a difference. But my cramps grew worse and worse and soon I was nauseous from the pain and had shooting pains only on my right side in the pelvic area, down my legs, and in my lower back all day and had to leave work. I went to the bathroom to change my tampon because I could feel it start to overflow and when I pulled my underwear down there was a clot about the size of my thumb that was very dark red at the end but was also very thick and light pink or fleshy colored with a weird shape to it and a long thin piece hanging off. Since that came out my cramps are going down a lot. I'm not sure if it's realistic that I had a miscarriage but had 2 negative tests but after doing research online and comparing pictures it's identical to what I experienced and had come out of me. If anyone has gone through this or knows of anything similar to this I would love the help. I can't get an appointment with my gynecologist for a couple days/weeks and I am really worried and confused. Thanks!