I've been on Zoloft 50mg for about a year now. This past week all of my symptoms are flooding back. Feel worried and anxious all day. Waking up shaky and lightheaded with in a few minutes of getting out of bed. Back to have bad dizzy spells for no reason. Had a panic attack at the grocery store today. Haven't had one in almost 6 months. I'm just starting to fear blood pressure or blood sugar problems. Not to mention the heart attack fears! My husband says my body has probably but up an immunity to the zoloft. Any advice or insight would be great.