For starters get the Allstays Camp & RV App. It costs $10 but is well worth it.
Try Tomaka State Park. You may not get a week or more on one site, but I just checked the 5 day period (during the week) from Feb 10-15 and 7 sites were available including site 34 which is a great site.
It helps also if you don’t need hookups. Lots of sites available in the Ocala National Forest. I can also guarantee you a site in the Everglades at the Lone Pine Key Campground (close to Homestead, Fl) if you show up on a Sunday night. It doesn’t take reservations and you can stay up to a month I believe. It is one of my favorite campgrounds. Here is a photo of Tomoka and Lone Pine Key.
Dan
