have been taking zoloft for 15 mths, gradually gone up to 300mg, ...

have been taking zoloft for 15 mths, gradually gone up to 300mg, and have been on that dosage for 10 mths. have experienced most symptons, dry mouth, vivid dreams (bad) tremors, weight gain. have recently had suspected seizure and have had eec, cat scan and am waiting for mmr . I have pins and needles on right side of head, involuntary spasms,, vague days and extreme tiredness. I could sleep most of the day and at night. I have to be very careful not to over exert because symptons are worse. have been worried about symptons being like ms but having visited this site am wondering if it's all down to the zoloft. Iwant to stop taking it.