Need some help

So I had my second child in November of 2021.. and I canceled my appointment for my depo shot the week before the six which was the day I was supposed to get my shot and I nerver got it bc we have been trying to get pregnant.. and the confusion part is when I go on depo, it stops my cycle completely and I don’t know when my last cycle was or nothing.. so I took a pregnancy test this morning and it came back negative but I am still getting the symptoms so I don’t know what to do..any suggestions would be appreciated