Kim (renter, month-to-month, landlord)

[Heidelberg]

Hi - I am a month-to-month renter in Florida. I had a one-year lease which expired and had no automatic renewal option. As a month-to-month renter in Florida I know I only have to give a 15-day notice. When I moved in I paid First, Last and Security Deposit. I advised my landlord today I would move out March 31st, and he should apply my prepaid "Last" month's rent he has already received for this month; the rent was due today when I advised him I was moving out.
He said I still should pay for March in advance since I didn't give him a 15-day notice before the March payment was due. Sounds crazy to me, but I told him I would go ahead and pay it and he could turn around and give it back to me when I moved out. I already mailed the payment today. Should I stop payment on the check since he already has my last month's rent that I paid when I moved in in July 2006. Help. Some people have told me I should not have sent him that money today.