Yes. You will have 60 days from the day you lose coverage to enroll in a new medical Insurance plan.
a) For companies with 20 full time employees, they must offer to allow you to keep your insurance and take over paying the premiums via COBRA. COBRA premiums are often much higher than you paid through your employer.
b) ALL Individuals, regardless of the state, or size of employer, qualify for Special Enrollment following loss of coverage due to no fault of your own. (Examples of fault: failure to pay premium, canceling coverage voluntarily)