I'm sorry that you are dealing with these difficult symptoms, and that are interfering with your daily life and the regular routine that you want to continue
Exercise is usually regarded as a good thing when treating PCS, but I don't know if your strenuous routine and weightlifting is too much, and may be making your symptoms worse. That is something to discuss with a neurologist.
I don't know how many doctors you have seen up to this point, but sometimes it takes a fresh set of eyes and someone with more training and experience to get you on the right path to successful treatment. I would recommend seeing another neurologist for evaluation and treatment.
I'm so sorry that your friends are talking behind your back. It's sad that they think your suffering is "funny." Part of that is immaturity, but it sounds to me like they're acting like ********, and if they were good friends, they would be more sensitive to your feelings. 16 is a tough age.
I hope that you have someone that you can confide in without judgement
I hope you will seek further medical care… or at least advice from a doctor as to whether or not your level of activity is safe, or at least not contributing to your symptoms.
I hope you will keep posting and let us know how you are doing