I need help

Hello everyone my name is nicketa 25 years old I am married with a six year old and I ttc for baby number two , for two years now with no luck I have irregular cycle ,and been too many doctors and they say nothing wrong, my cycle nose has not come for two months I took a pregnancy test with a negative result, but I constantly have cramps in my stomach. So my question is what kind I do or take to regulate my cramps and why is my cycle act like this but I am not pregnant , can I get some advice from some of the ladies on here please and ThAnks it's greatly appreciated