I had a long discussion with my GP regarding the pill as I've had laser treatment for Maculopathy. I was still fine to go onto the pill and whilst diabetics can go on the Combined Pill, it's not recommended (as I've had some issues regarding periods and hormones, my GP did not want to put me on anything with oestrogen).
I was put on the mini pill in May and I absolutely hated it. I did not get on with it at all. I essentially had all of the possible side effects (weight gain, feeling depressed, heavy painful and extended periods, the longest at 35 days! etc). I came off of the pill in Septemeber.
I've been looking into other forms of contraception. The injection is okay for diabetics to have, it's recommended over the Combined Pill, however it wouldn't be the first choice. I'm unable to have the injection as I have heart disease run in my family.
The two I'm looking at though are the IUD (Copper Coil) and the IUS (similar to the Copper Coil, but different materials). The IUS is what I believe I am going to have, they both last for 5 years and aside from a slightly uncomfortable procedure and my GP said I should expect about 24 hours of bad 'period pain' afterwards, it seems to be an ideal solution for me.
I would definitely discuss all your contraceptive options with your GP and research into them. My GP printed off information from me and she went through everything that she would be willing to prescribe for me. As I'd never been sure of the IUD or IUS, I did my own research into that to find how women who had them found the procedure and the end results etc. That's what really sold me on the IUS.