Need advice!

So about about a year ago my periods randomly changed and now last 2 weeks-the first week very light and the second I can't even keep an ultra tampon in for longer than 2 hrs. My periods have been like this before. I let it go for a while and when nothing was changing I went to the dr. They did an ultrasound and I had a cyst on my right overy but other than that everything looked normal. The change could be because of the cyst.

My doctor told me that my period lasting 2 weeks is perfectly normal and to let it go or get an IUD (which I really don't want)

Should I get a second opinion? Or does anyone have any advice? I just find it hard to believe that it's normal for periods to last 14 days