Side affects of this medicine

I began this med.10 days ago because of a very bad infection on my back. I didn't notice much at first other than fatigue but since I had been in the hospital a few days before starting it for a cathater procedure to my brain, didn't link it with the meds. I saw my Dr. a week after she put me on the meds and told her I had a few spells of dizziness and lightheadedness. She had increased my Zoloft dosage and told me to cut back. I did but the past two days *my last two of the medication, I have felt terrible. suddenly start feeling weak in the evening (usually about an hour after the second pill) I finished them last night and woke this morning so dizzy, I could hardly stand up. Is this normal My BP has to be controlled with meds and ON them I stay between 120 and 130/84 This morning it was 110/78 and my pulse rate was 100. Could it be the meds.