Is Yasmin Pill, Safe For Endometriosis For A Long Term Use?

hello. I am 29 and I have endometriosis. Had surgery in May 2009 for this condition and have since been on Yasmin pill without a break for about 18 months now. I suffered with acne when I was younger and went took Dianette for 5 years from the age of 15-20 which cleared up my skin. I came off Dianette because it became inaffective. Eventually I was prescribed a course of Roaccatane which I hated and felt incredibly depressed on. Since taking Yasmin I have been fine but have recently (last few months) began to develop acne on my back again. I went to my GP and she suggested I switch to Dianette to see if it clears up my skin. However I am worried about this pill and its tendancy towards depression, mood swings etc and I'm keen to make sure that this is a good treatment option for Endometriosis as I have read that its not recommended for long term use. Please advise. Thanks so much.