Epilepsy and birth control

So I was recently diagnosed with epilepsy a year ago and I also have PCOS which causes me to be really irregular and my periods are absolutely horrible. Before I was diagnosed with epilepsy I was taking the pill and loved it, now that I'm taking medication for my epilepsy I have to be careful with the contraceptive that I use since they can cancel each other out. I recently got one does of the Depo (the shot for birth control) but I've tried it before and it caused me to gain some much weight and I don't like what I saw about the long term side effects. So is there anyone that can give me advice on which contraceptive I should try that would be safe to take with my epilepsy meds? Thanks in advance!!