How severely is your problem? High school is still pretty young to be taking these drugs at all. Did you try therapy? Did something happen to trigger this? But assuming a drug is necessary because your life is so severely affected you can't function, they all affect us differently. They also affect younger people differently than they do adults because your brain isn't fully formed yet and you have more energy and lots of hormonal things going on that mellow later in life. If you're on 25mg and feeling anything at all, that's pretty amazing, as specialmom noted. That means you're metabolizing it very well, which means you'll have worse side effects but also it will probably work better. Because it seems to be helping at such a low dose and so quickly, it's likely the longer you take it the better it will work, and it's also likely start-up side effects will pass. If they don't, it's not the drug for you. But I'd seriously consider if any drug is necessary for you at your age. You know better than I do how bad your life has gotten. Whatever you try, be patient.
These medications can work well but it takes 6 to 8 weeks to judge how they work on you. That's a fair trial time to stay on it to see. Start up side effects or transient side effects happen but they peter out the closer you get to that 6 week time frame. 25 mg is super low, SUPER low for Zoloft. Good way to start but would be surprised if you were not titrated up to 50 mg or more for a therapeutic dose. I'd stick it out to see if it works. good luck