I am sorry to hear about the ectopic pregnancy. If they removed the Fallopian tube, that can cause changes to your cycle which may be temporary or permanent. (Removal of any part of the reproductive system can alter or even shut down ovarian hormone production even to the point of a surgical type menopause.) However, you could be starting perimenopause even though you are on the young side.
I've never heard of Asherman's before. Thank you for your reply. I will definitely ask about it!
You might have some scar tissue that is affecting things. I'd ask the doctor if an MRI can be done of your uterus and abdomen. You want to rule out Asherman's. (It can be dealt with by a minor surgery if you have a lot of internal scarring in the uterus.)