What should I do if my employer didn't deduct FICA taxes for me?

Currently, I just noticed that I should be the resident alien instead of non-resident alien as the cumulative time I stayed in U.S. is more than 5 years. However, my previous employer didn't deduct FICA taxes for in 2019 (they didn't ask me if I'm RA either). Now, it's the tax season, what should I do when I submit tax forms?