Hairs really oily at night after I sleep.

So my hair get like really oily after I sleep with clean hair and idk if it the shampoo I’m using or something but I have such oily hair in the morning and have to wash it again even tho I just washed it the day before. No I don’t go to bed with wet hair. Just wondering if there is a way I can cut the oiliness down and it’s only started recently cause I’ve never had the problem before now I haven’t change shampoo or anything in the last couple months. If you have thing that would help that would be great. I have shoulder length hair and bangs.