Did having 3 previous c-sections cause me to get an ectopic pregnancy ?

Possibly: Repeated pelvic surgery, which includes a c-section can cause the formation of scar tissue (adhesions) which can block your fallopian tubes (which carry the egg from the ovary to the uterus) and then cause an ectopic pregnancy. This is because the fertilized egg cannot reach the uterus to implant where it belongs. Repeated c-sections are associated with reduced fertility.

Probably not.: Although cesarean sections have many adverse implications for future reproduction, increasing the risk of ectopic pregnancies is not one of them. The adhesions caused by cesarean section typically do not involve the tubes, rather the bladder. When the tubes are affected, infertility can occur, as can ectopics. I am not aware of any good data to prove a link with ectopics, though.