Why does trazodone make me feel weird the next day? or could it be from not sleeping well?

Could be both: Depending on dose & when you take it, some trazodone may still be in your system the next morning. If you haven't yet had a thorough evaluation of your insomnia, it would be wise to do this. Insomnia can have many causes, and medicating without knowing what you're dealing with may be frustrating. A psychiatrist or sleep medicine doc can help. Good sleep hygiene may help even more.

Trazadone: All medication can have side effect trazadone can cause sedation , orthostatic hypotension among others, so be careful when driving , but the side effect can also depend on the dose u taking , talk with u physician about it.

Sedation?: Feeling odd may be related to the trazodone or to lack of sleep. About half of the patients I have treated with trazodone find it very effective & tolerable & about half find it too sedating the next day.