Not sure if im pregnant or not.

So my son is 17 months old and ive been on the depo since the hospital. Within the last couple of days my stomach has gotten bigger and it looks like im pregnant. This would be my 6th pregnancy, i have 2 kids and 3 previous miscarriages. i feel pregnant, my boobs are starting to itch and im more tired then normal however all the pregnancy tests ive taken are negative. Today i feel and look extremely bloated and i feel full. With my son i was already getting a pouch before i found out i was pregnant. Idk im just very confused. I dont get a period since im on the depo.