I have been on depo provera for 3 years now and recently have been throwing up last week I decided to take a pregnancy test and got 2 positive results but the lines were not very vivid... My boyfriend asked me to take another while he is present because he doesn't believe me. I went to take it and noticed I was bleeding very heavily and the day before had very intense abdominal pain... I have not had anything more than spotting since I started depo and yesterday I bled through 4 tampons in under 2 hours. Today I took a test and its negative and the bleeding has somewhat stopped. I have a doctors appointment Thursday but really need answers asap

You can get pregnant on depo, but it's extremely rare. Unless the injection itself was ineffective (bad batch of the drug, etc), you'd have to actually miss it or receive it late to open a window. Even if that happened, I think it would be still unlikely for you to become pregnant if you've received all your injections consistently for that length of time. Women who go off the depo to have a baby will not conceive for several months, and sometimes a few years as the progesterone levels (the hormone in depo that prevents ovulation and thus pregnancy cannot occur) gradually decrease.

All of that said, I'm glad you have an appointment. If you're reproductive age and "normal" suddenly isn't, that's the best plan.