can I find out if I miscarried months ago?

 This happen while I was on depo my first shot. Before this happened I was at the grocery store and I felt the need to take a crap really bad I began having really bad cramps and when I got home I felt something come out me. I'm thinking ok my period. But it was this! I did go to the doctors and they couldn't tell what it was because it became unnoticeable when I went to the doctors with it in the tissue in a container. They said it's not a miscarriage but they didn't do an ultra sound on me. I'm thinking now what if that was. Is there any way I can find out if I miscarried months ago. I wanna say this happened in November or October.