What Are The Side Effects Of Depo Provera Injection?

I took the depo june 4 ,I had aperiod and I was due in august for next shot but never got it,september I missed my period and october I. Spotted for 10 days and now this month november stlii no period or no spotting I'm having morning sickness and craving and pee a lot. I had couple HPT but all came back neg 3 days ago I went to the ER during the pelvic exam the doctor said I had no infection but my uterus was slightly enlarged.could I still be pregnant even I get neg results or its the depo that I came off bcause I'm still wondering why am I peeing so often and what cause my uterus to enlarge slightly?