I am 13 days late on my rent, because my ssi check was stopped by mistake. Getting a make up check 1st of March. He locked me out yesterday.

ANY question on law needs to include your general locale as laws vary by area.

Your first step is to call the police. Tell them your landlord has illegally evicted you and you need to get back into your home. I'm assuming that you can prove you do live there.

Its possible the police will not allow you to stay but they should allow you remove your belongings. The next step is to hire an attorney and file suit against the landlord for an illegal eviction.

All areas have an eviction process that must be followed to remove a tenant. If the landlord did not follow them (and it appears he didn't) then you have grounds for an illegal eviction suit. If the police don't help you then contact an attorney immediately.