My daughter has been on sertraline for 4 weeks for anxiety/depression. she is worse than before. are extreme ups/downs normal at this stage?

Yes: Mood issues and response to medications can be complex in this age range. Generally if you have not seen a positive response after two weeks on medication contact your MD for recheck. Consider asking for MilleniumPGT testing - I use this in my office to help determine if there is a metabolism problem with different behavioral medications. This may explain poor response. Make sure on vitamin daily