14 mm thickness on uterus

Hi been drs got result of my ultra sound about been told I have a 14mm thickness obviously anxiety goes in to overload ! I believe said in one side . The ultra sound was about a week or two before my period was due I now have been told to have a second ultra sound I’m 37 ( I think, I got to stage I stopped counting 😂) has anyone else had this . What prompted investigation was two abnormal heavy prolonged periods no pain . This month most normal period I’ve had in a long time x

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