Last Night I Was Going To The Bathroom And Suddenly

Last night I was going to the bathroom and suddenly felt nauseas and then the sweat set in. Once I stood up I fainted and hit my head on the tile very hard. I don't think I was out for more than 30 seconds. I still felt sick for about 15 minutes and then it seemed to pass but my head hasn't stopped throbbing and I have a large goose egg. I am otherwise a healthy 38 year old woman with the exception of having triple negative breast cancer 3 years ago. I underwent 16 rounds of chemo and a double mastectomy and had a complete response so I have been in remission now for a little over 3 years. My question is: Should I go see a doctor about the fainting episode? and also possible head trauma due to the fall?