No period after depo

So I started the depo shot Jan. 2018 after I had my son. I took it consistently every three months without missing. My next shot was supposed to be Nov. 12 but we decided to start trying again so I didn’t go get it. I had a period late October but since being off of the shot I haven’t had one. I started having symptoms that I only had when I was pregnant but I also am having the symptoms of a period starting for two weeks now. I took a pregnancy test and it was negative but when I got pregnant with my son the test didn’t come up positive until I was over 5 weeks. So my questions are has anyone else went through this? How long after depo did it take you to have a period?