Are there negative effects to coming off the pill?

Months. It sometimes takes months for periods to settle down after coming off oral contraceptives. I note that you are 36 years old. I suggest seeing your ob-gyn. An ultrasound of your uterus could be done to measure something called the "endometrial stripe" to see if it is too thick. If so, it could be shed by using a medication like Progesterone to cause it to slough off and return to normal.