I am a law school graduate. What I offer is mere information, not to be construed as forming an attorney client relationship.
It all depends on if your state is an "at will state". This means either you or your employer can walk away from the relationship without notice and with or without cause. That does not mean to say that wrongful or discriminatory termination is okay either.
As far as health coverage, you need to know what your individual policy is and whether they have a right to terminate benefits after a certain point.
On both, to get specific answers and solutions to your issues, please contact an employment labor law attorney in your state. You can either go to attorneypages.com or contact your state bar and ask for the lawyer referral program.
Hope this helps.