I don't know about shampoo but I've been told (face) skin gets greasier the more soap you use - it tries to compensate for the protective layer it loses by soap

I don't know about shampoo but I've been told (face) skin gets greasier the more soap you use - it tries to compensate for the protective layer it loses by soaping too often. So you might have been caught too in a positive reinforcement loop?