Can polyps cause thickness of the womb?

I had a small amount of bleeding (I'm post menopausal)but not old. and I went through ALL the tests, hysteroscopy, lots of pelvic examinations, blood tests, whatever else can be done and ALL the results were ok. They only found a polyp and it was nothing to worry about. The slight bleeding stopped for 2 years, now I had some bleeding again, went to the doctor, had some examination and my womb is 7 cm tick. Is that too much? Can polyps cause that? is the polyp back?
The doctor took some material from the womb and I'm really worried, however, she did say everything seems to be healthy and she thinks that it is only the polyp again. Question: Can the polyp cause the womb to be 7 cm tick? Please somebody answer, I'm quite distressed