Lithium Carbonate and stomach

I have been on 1500 mg of lithium day and never really had too many side affects but recently i have been gettin really bad headaches,anyone else have this problem?

I am up at this moment, because my stomach is hurting from the lithium. I've been on it now for about a year, but my stomach just started hurting at night after about an hour after taking it for about three months now. Is anyone else experiencing this? I read one post above about it, but that's all. There is no vomiting, but just upset stomach. It keeps me awake. I'm on lithium and lamictal, and Topomax. If you experience this, is anyone taking anything for the nausea? Thank you! And everyone hang in there! You're in my prayers! Don't give up!