I was on Zyprexa a few years back and I gained a lot of weight wi...

I was on Zyprexa a few years back and I gained a lot of weight with it due to increased appetite. In my case this was not a problem as putting on weight was something I needed. I am back on Zyprexa for a couple of weeks now. My appetite has increased again and I suffer from tiredness a lot. I have been suffering with headaches too but i'm not sure if this has anything to do with the Zyprexa. Headaches are not a side affect reported on the leaflet that comes with it so is it possible that Zyprexa is causing these headaches?????????????????