help me!

aimee
I got the injection 3 months ago and I'm due to have it again Tuesday, I don't know what to do as it has really messed up my periods. I've been on and off for 3 months now! instead of having a month inbetween I've had days!! this isn't normal and it's effecting my sex life also. has anyone experienced anything like it? should I still go back to have it again because it could stop them after my second shot, I really don't know what to do! any advice?