Employment Law Questions? Ask an Employment Lawyer.
Hello and thank you for entrusting me to assist you. I am very sorry to hear about your PTSD and the problems you are facing with your employer.
As for your question, there is no legal significance in them calling it "administrative leave." They can call your absence from work whatever they want, they just cannot take adverse employment action against you because you took FMLA leave (i.e. they can't fire you in retaliation for it).
I hope that you find this information helpful. Please do not hesitate to let me know if you have any questions or concerns regarding the above and I will be more than happy to assist you further.