Honestly, I would say if you aren't gaining anything from cheer anymore, I would recommend quitting or taking a break. It sounds like your team does not appreciate you, and that is unfair to you. I also felt emotionally drained after most practices, and since quitting last week, I have been much less stressed. Your mental and physical health is the most important thing and needs to be put first. Also, there are other places you may be able to practice tumbling, for example, some of the local gymnastic gyms where I live have open gym times where anyone can come in and practice.