Spotting changes

So over the past year or so I have seen a change in my period. It used to come on strong and sudden. Now I will get lightly tinged (red or light) brown discharge for a day or two (sometimes three or four days) before it starts. I’m not sure why this has changed, anyone have something similar happen? Only questioning this because I’ve been trying to get pregnant for 2.6 years and nothing. (I have been to 2 reproductive endos and both say I’m unexplained)