Medicare doesn't have an income limit. But you have to be on social security disability (SSDI) or retired on social security and you have to be on SSDI for 2 years before you qualify.

Obamacare sounds best for you. There are no pre-existing condition restrictions anymore so that shouldn't affect things for you. I don't know how that works but I'm sure someone does.

It sounds like maybe considering a short term disability break if that's an option for you may be best. If you don't get better now working then you have a clue that you may want to apply for SSDI or SSI (depends on how much income and quarters working you've had over some time frame I no longer remember but want to say is 10 years).