Brown Spotting

I am 38 years old and for the last six months I have had continuous brown spotting in between my periods. I have periods for 4-5 days then 1 week of no spotting and  then  again spotting for 1 week to10 days followed by  periods. I am getting periods every 15-17 days.
I have no children, my ultrasound early in the year was absolutely clear. I have borderline hypothyroid and have been gaining some weight last 1 year on wards.
Sometime during spotting period I do get some burning sensation near the cervix. I used to have bad cramps that have all gone. So far I did not feel fatigued but during the last period I have started feeling fatigued. I have completely stayed away from any intercourse as this is bothering me. I am undergoing menopause or something else is the issue?