i was diagnosis with clinical depresion and social anxiety since 09 and i couldnt believe it in the first place as well . i was then admitted into a Juvenile wards in springfield university hospital . i m now out as out-patient in farnham rd hospital ,like you , i m 18 as well ,i m on and off medication for a bit more then a year now . i was back on zoloft a couple of month ,it is a sedative medication , normally starting dose as 2.5mg then move on up to 10mg . it help me to sleep a lot better and help with my psychosis .but it put on heavy weight gain , 15kg in the last 3 month . some medication can also cause servere side effect such as suicidal thought but it depends on the own person . i suffer servere suicidal thought while i was on sertraline but now i m back on prozac ,tell your doctor immediately if so ,but i m sure they will take good look of you since you are in the hospital . i still sometime suffer from suicidial thought but it prob just me not the medication.hope all go well for you . anti-depressent is not as amazing as normal people thought as the magical pills. thearpy should also be apply for the best effect out of it. you need to give it time and slowly find the best med for you and the best dosage to balance the side effect and its positive effect on you .x