When I divorced my first husband I kept his name then I remarried using my maiden name am I legally married?

Yes ! Look at your marriage license - is the license issued in the correct name?  If it is you are fine.  If it is not, you can always correct the documents, but there really is no need.  Did you get a marriage certificate from the Court or religious ceremony?   As long as that certificate says the name you want it to, you are fine.