I Suffer From Migraine Headaches. I Was Shopping With My

I suffer from migraine headaches. I was shopping with my son this week and he was putting the tailgate on my 4Runner down and accidentality pushed it down and it hit me in the back of the head. I have been dizzy and nauseous for four days and still have a pounding headache. I'm thinking that I should go get a CAT scan to be safe. Do you think that is necessary? Or should I just keep putting ice on it and monitor it?