I was prescribed Lithium a couple years ago. IIRC I started at like 300mg and my doc titrated me up to 900mg. I took it alongside Abilify 30mg pills. Lithium was the only psych med I've ever taken that I could feel. I mean, Seroquel made me extremely tired, Risperdal injections gave me all kinds of awful side effects, but Lithium from the beginning, gave me some sort of tingling sensation throughout my body.... almost like a mild weed buzz.
Of course after a month or so, Lithium also caused me to get hypothyroidism. I first noticed when I became tired all the time and began napping frequently, which I was not normally doing. Got some blood work and I had 2 choices, either keep taking Lithium and add some thyroid meds that I would have to take the rest of my life OR stop Lithium and switch to another mood stabilizer. I switched to Lamictal and am now on 200mg and still take Abilify. No real side effects and feel pretty even.
Now like we say all the time, each of us has different side effects to every medication so what happened to me won't happen to most other people. If Lithium works for you and your blood labs are okay, I don't think it will hurt to continue taking it or increase dose if needed.
Like negrogesic said above, if you tell us your current dose and the increase amount, we will have more info to go off of. However, none of us are medical professionals so all we can really do is give anecdotal subjective statements.