Did I Have A Miscarriage?

Hi, about 1 month and 1/2 ago, I took 4 pregnancy tests to ensure that I was not pregnant. 3 had a faint 2nd line and 1 was inconclusive. Later, I was told that a faint line was a positive result. My menstrual cycle had skipped 3 months. Well, it then came on 2 weeks ago with extremely heavy bleeding and almost unbearable pain and cramps. A friend told me to take another pregnancy test. I did and it came out negative. I'm not sure if I was pregnant. Could it have been a miscarriage?