All of my other residents in my program said that there was a 2000 dollar rebate if I was still in school last year, and I definitely didn't fill something out to receive it, and was told I was still able to amend my returns to receive it, but not sure exactly what to fill out.
You can amend, but there is no magical $2000 rebate.
If you were claimed as a dependent by your parents, they received any credits that you might be eligible for.
The American Opportunity Credit is the only credit that can give you cash back even if you don't work, and that is $1000, only applies to the first 4 years of undergraduate school, and you can't get the extra cash unless you are 24 or older or your parents are dead. Otherwise, it goes to your parents (if you are a dependent) and if it goes to you, it can only reduce your taxes owed to zero.
For medical school, only the lifetime learning credit is available. It will reduce your taxes by 20% of your tuition paid up to $2000 ($10,000 of tuition). But it only reduces your income tax. If you worked and paid withholding you would get a refund of your withholding. It doesn't come back as a refund if you don't work and owe no taxes.
If you used turbotax last year and are not a dependent and you entered your 1098-T, you already got whatever you qualify for.