9 weeks after ectopic surgery and still no period....

Hello everyone, it's been 9 weeks since I had surgery to remove my right tube for an ectopic pregnancy (9/16/17). two days before the surgery I had found put it was a tubal pregnancy and they gave me 2 shots of MTX in hopes that they caught it in time but then a couple of days later I was in so much pain I had to go to the ER and they did a laparoscopic to remove the right tube. I was 8 weeks pregnant. It was a very heartbreaking experience. Here I am 9 weeks later and I still haven't had a period and I have been experiencing quite a bit of pain on both my right and left sides the last couple of days. I took a hpt and it was negative. So my question is, what could be causing the pain I'm having right now? And has anyone taken this long for their period to start after ectopic surgery?