Why Am I Having Pain After Taking Cerrazette?

hi, i am 23 and generally in good health although i am overweight. i took cerazette POP contraceptive pills for 2 years with no problems. I started gettin pain after sex and then in january this year i had excruciating pain lasting 4 weeks (no bleeding) after a trip to the A&E I came off the pill and had no problems (periods returned with manageable pain). to avoid pregnancy I have started taking the pill again as i have been advised by my family planning clinic that cerrazette would not of caused this problem. i have been taking the pill for a week and I am now experiencing a similar pain as before. I would stop taking it but i feel the pregnancy at this time would be a bigger problem. (condoms are not always an option as my partner is alergic to latex and we find it difficult to get hold of latex free condoms) please help, thanx, jenny