I have Medicaid, do I need some other kind of health insurance besides the Medicaid?

I have Medicaid health insurance(haven't used it yet), but read somewhere that it doesn't cover much? Do you know of any affordable health insurance I can also get-don't have much money. Are there any organizations you can join to get health insurance? Am I allowed to have other health insurance even though I have Medicaid. I live in Massachusetts.
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Some people get confused over whether they have Medicaid or Medicare. Medicaid is welfare from the state for very low or no income persons, Medicare, sometimes referred to as the red, white, and blue card, you get automatically when you attain age 65 or if you are disabled, you get in your 25th month of disability. I think you must have Medicare and you absolutely need a supplement and Part D to go with it. If you do have Medicaid then you don't need anything to go with it and you couldn't possibly afford to pay for it anyway. Take out your card and look at it it will say Medicare or Department of Community Affairs, you will know then. Best wishes.
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