I would say try to do 30 mins. I feel 90 mins is too long and that is the problem. You need a technique to blot out your thoughts. Mine is to name things for ev

I would say try to do 30 mins. I feel 90 mins is too long and that is the problem. You need a technique to blot out your thoughts. Mine is to name things for every letter of the alphabet. I start with fruit and veg - apple, banana, cactus (rhythm wins over accuracy!). Mostly I don't remember reaching Z.