Periods and spotting problems. Cancer?

I am a 38 year old woman. I have pcod, hence At times I get my periods on time but mostly my cycle is 45-60 days or even more. My cycle usually lasts for 5 days, this time I got my periods on 31st august and my periods was normal till my 5th day . But on my 6th day I noticed blood flow all of a sudden and it continued till 7th day though the flow was normal. On 8th, 9th and 10 th day I experienced clotting once in a day with good amount of blood going out. Once the clot is out, bleeding stops completely till 24hrs. 11th day there was no spotting, but from 12th day(yesterday) and today I can see mild spotting with brown discharge once. The spotting is so mild that it disappears .Today I went to see my doctor, she isn't in town so her assistant doctor consulted with me. She pressed my lower abdomen and told me this is not an issue and it may be due to stress. She told me to get my TSH done as I take 50mg now and haven't done the test post pregnancy. Do I need to worry about cancer?