If you are essentially maintaining by eating 3000 calories, try eating 2700 and see if you start losing - it should be slow, because you are at a healthy weight (I'm assuming you aren't underweight - if you could provide your height, that would make me feel better). Slow is good - slow is healthy.
No, you should not be eating 1500. That's the bare minimum for a sedentary teen. You do track and soccer - not at all sedentary.
The 3000 calories that were you eating "out of control for weeks" only led to 1lb of water weight - so it's probably a good estimate for your maintenance calories. It's not "out of control" for a very active teenage girl - it's a reasonable number for you to eat to maintain your weight. So eating a few hundred less (2700) will allow you to lose fat slowly and healthily.
110 lbs would be too thin for 5'5. 120 is a fine weight, thin, and honestly probably the lowest (or close to it) you should go. Your BMI is 20 which is already pretty low. At 110 lbs you would have a BMI of 18.3 which is underweight. Don't do it!
The side effects of allergy medications keep some people from using them. Natural remedies can be a great alternative, but some are more effective than others.