My question involves labor and employment law for the state of: PA

Hello,
I am currently on ttd due to a work injury. I had surgery and then was placed on light duty. My pain started getting worse and I was placed out on ttd again. I gave doctors notes to my employer each time.

I recently received cobra notification that my employment was terminated so I have no more health insurance.
I do not know the terms of my termination but I assume it was due to missing too much work.

So far this year I have missed about 5 months of work.
The entire time I was out my employer never called or sent any information regarding health benefits or the payment of the employee portion. My health insurance continued so I assume the employer was paying it.
I also never received any information regaring fmla nor had any conversations about it with anyone at work.
My ex employer has way over 75 employees and does qualify under fmla rules and so did I.

Here are my questions:
Is it true that the employer must notify an employee that time off is designated as fmla as soon as they have reason to believe the leave may be covered under fmla?
What are the repercussions if they do not?
Is it considered interference with fmla if they terminate me after not designating time off as fmla?
What should I do now to protect myself?

Thanks,
Biglayman