Zoloft is pretty OK stuff. The first two weeks the side-effects will make you a bit woozy, but in a good way. It takes about 21-45 days for the desired effects to kick in. This depends on metabolism, body weight, etc. As others have said, it will eventually be useless after prolonged use. As Jimmy(?) said, once you get up around the 200mg dose range, your Doc should think about moving you to something else.
Learn from my experience with it-
DO NOT drink on this stuff for the first few weeks. Trust me on this one. You really shouldn't drink on it at all because it amplifies alcohols depressant and inhibition effects. However, some folks cheat. I did, but I am far removed from anything like heavy drinking now a days.
Stay in touch with your Doc. They always start you out on small doses. They will have to increase it over time. This stuff is so mild and so rarely toxic that the usual high dose issues do not apply. For example: a higher than average dose is 25mg three times daily.
While often prescribed as an antidepressant, in reality it is a stabilizer. It does frak around with your neurotransmitters, but in a good way. It has been shown to be extremely effective in combat PTSD cases. In my case it worked so well I was only on it for about nine months.
Enjoy sleeping while you get used to the side effects. You will know when you have gotten used to it because your sleep patterns will return to what is normal for you.
Drugs.com will give you the general down-low better than I can.
Zoloft/sertraline is one of the few pills I actually support in our treatment regimens. I have yet to meet any vet in person that has not had at the least a small measure of success with it. It won't fix you, but it will smooth you out enough to allow you to get your bearings and focus on your treatment.
Oh, by the way, take this one with food or milk. They are uncoated tablets and you can get some nasty burns in your esophagus if you do not. I learned this the hard way. Picture the worst heartburn ever, except it is caused by rabid wombats humping in your sternum and last for days.