TTW, is this a miscarriage or just tissue?

around a month or two ago I passed a tissue sort of the same as the image below at work. the tissue wasn’t soft instead it was hard (kind of like a clay texture? or putty texture?) and today I passed more again. it felt like a regular heavy period passing through but when I went to examine it I saw this instead. ive been safe every time and im on the depo provera shot but im scared i may have been unlucky. this might come off as very irresponsible to post as I’m only 16 and have a life ahead of me but i just wanted an opinion on it as my mother refuses to speak about pregnancy with me