tired

I know this is whining, but does anyone else get really tired after they get Herceptin? I feel exhausted the day after. I don't know if it is the radiaiton still(i finished a month ago) or if it the herceptin. How long were you girls tired after radation? What helped? i feel like i'm 80 years old needing to nap after i've just gotten out of bed!! I hope its now my heart. I go for a muga next week.