Have been taking flumadine (rimantadine) and I still feel the side-effects?

Flumadine (rimantadine) This is antiviral against influenza a, taken for short period, maximum 2 weeks can cause irritability, dizziness, insomnia, hallucinations---- could be allergic, or taking too much, or having drug interaction with another drug-- you either will get used to side effect or stop taking it it does not work for some influenza types.