tumour

I was having heavy periods and my regular doctor sent me to get a couple internal ultra sounds a month a part.  Apparently I have what the radiologist called a tumour, 5cm.  My doctor sent me to a gyn.  who tells me he is taking out uterus, both ovaries and both tubes, immediately. Should I be worried?  I have also had back pain for about 3 months, prior to this.

[justwaiting]

The doctor said it was on my right ovary, but to be safe if it does turn out to be cancer, there won't be a need for another operation.  I live in Canada and my doctor is a gynaecologist/obstetrician, is that the same as what you call a gyn oncologist?