Could Prolonged Bleeding With Heavy Clots Be Due To Miscarriage?

I ve been on the depo for almost 9 months now. I ve been on my menstural cycle for two and a half weeks straight . Today I have been having horrible cramps so I took Advil. When I got up to use the bathroom and finished on the toilet paper was thick mucus that was dark bloody with a grey tent.. Ever since I used the bathroom I ve had worse abdominal pains and Lower back pains. Could this of been a miscarriage ?