pregnancy symptoms on depo

Good morning everyone. I have a question I would like some help with. I am a 27 yrs old with 2 children, 3 and 1. I have been on and off depo since I was 15. I have been on depo for about 6 months now after trying mirana and having problems with it. Since I started the depo this time i had no bleeding or pms signs (till now). 2 weeks ago I started getting headaches that refused to go away, changes in bowel movements, nausea, extreme mood changes, fatigue and saturday morning i started to bleed bright red but it was not a heavy flow. I was bleeding again last night and i am just confused because this is unusual for my body when i am on the depo shot. Can anyone give me any advice? I hate going to the dr cuz they seem to just shrug things off! Thank you and Merry christmas eve!