Personally, I think it’s very smart to get a second opinion. (I was going to suggest it! 😉). You’re young to be having anemia without further evaluation to find the cause, especially along with the other symptoms you’re having. Sometimes you just have to go with your gut instincts on matters like this when you really feel something isn’t right. You know your body and have to be an advocate. I’m older now, but I remember having some issues when I was younger, around your age. I felt dismissed by the doctor who didn’t take me seriously. He failed to do a complete workup on what was happening with my health. I changed doctors and had a very positive outcome. It’s definitely good to change doctors when you’re not getting answers. You have a valid concern that warrants investigation!

When you see your new doctor, have a list of questions you’d like answered. Just list them off the top of your head for now, to get started, then edit.
Also, it can be helpful to have a list of your symptoms and when they began. Little things to consider that may spark memories to get a comprehensive list:
When this first happened, what did you notice first? Were you ill? Did you have Covid, a vaccine, a cold, sore throat, etc. Do you have heavy periods? How frequently do you have night sweats. You mentioned your hair is thinning, make a note of that and anything you can think of that has changed or is relevant to your health since August.

It saves time in those initial appointments to have everything jotted out or notes on your phone so that you can go right down the line and address all your concerns.

I’d like to follow along with you on this mission to find answers. Will you keep me posted to what you find out?