experiences with depo??

I've been on deli for almost three months now and at first it was great but now that I'm a week and a half away from my second shot everything is going to shit! I've realized my sex drive has crashed completely, I still enjoy and want sex but I don't get horny from the normal things that would turn me on anymore. I've been very moody and depressed, I was getting very dizzy and almost blacking out last week. What are everyone else's experiences with depo? I'd like to stay on it for the convenience but not if it's harmful