Deprovera Don`t Do It

I have been on the shot for a year i am due for my next shot tommorow and i am very confused about what to do i have three children already and do not want anymore right now but the shot has awful side affects i bleed off and on all the time which puts a damper on sex i have terrible headaches and i constantly take pregnancy tests because i feel pregnant all the time i have noticed complete loss of energy and terrible mood swings so bad that my Dr put me on hormone patches thinking that it was an embalance but it has not helped i have body aches and i am only 26 and looked like i have aged quite a bit in just one year and i really believe it is from the shot because i never experienced any of this until the shot i also had an IUD that caused pelvic inflammatory disease i am at my wits end i don`t know what to do about birth control and don`t want to get pregnant until i finish my nursing school