I've recently change my contraception, I was on the mini pill for about a year and a bit, in the last few months of being on it I kept getting heavy periods which I haden't had since I got put on it, I went to the hospital and the doctor told me it may not be working with my body, and advised me to change it, so I did, and I'm now on the injection which I had about a month ago, I'm still heavy bleeding, but on and off, so when I'm off I have had sex with my partner but after bleed really heavily, is this right?