Federal Regulation 26 CFR 301.6362-6 states:

"An individual who becomes a resident of a State pursuant to subparagraph (1) of this paragraph (b), or who is at the beginning of a taxable year a resident of a State pursuant to such provision, shall be treated as continuing to be a resident of such State through the end of the taxable year, unless, prior thereto, such individual becomes a resident, under the principles of subparagraph (1), of another State or a possession or foreign country."

https://www.law.cornell.edu/cfr/text/26/301.6362-6

Thus, if you were a Florida resident in the beginning of the year, for tax purposes you remain a Florida resident until you establish residency in another state.

If you have self-employment income, you would file a non-resident tax return in whatever state or states you earned that income (assuming that your self-employment income exceeded the filing threshold for the particular state).