Why am I so tired no matter how much sleep I get?

I have been sick this year and my doctors finally found a carcinoid tumor. It was removed a couple of weeks ago and I have been feeling better. However the last 4 days no matter how much sleep I get I still feel so tired. My sleep patterns have not changed. I get roughly 8 hours of sleep most nights. There were no signs of it spreading. My followup appointment is later this week. Should I bring my tiredness up to my Onocologist?