i am on the medication invega. I have received the shot ever since October first, or almost 3 months. I am experiencing muscle stiffness and pain. at times my heart's rate is elevated and has a weird rhythm. I also experience tiredness, weakness and I also become dizzy when standing. I also experience some other symptoms but these are the main ones. I am a 53 year old female and I also take welbutrine and sertraline. I am laying around all day and I have pain that is limiting my activities. concerning the side affects, would you discontinue use of invega.