Loss of FOX (Ch12), CBS (Ch10) and maybe (you said "not sure") NBC (Ch11) are ALL in Hi-VHF Band [so is one of the two PBS stations on Ch13+34]....which is much more susceptible than UHF to Man-Made Interference [e.g. CFL/LED/Fluorescent Lights, Dimmers, anything with a Motor and perhaps a dirty Switching Power Supply used to recharge SmartPhones and power Laptops, etc.]. So try turning various lights and appliances (e.g. Dishwasher) OFF AND ON to see if you can identify the culprit. You also might want to shut down ALL Circuit Breakers except the one feeding your TV to see if the problem goes away....perhaps it's HVAC Fan, Pool Pump or Well Pump??? And don't rule out your Neighbor(s)....
Hi-VHF Band propagation is also affected DIFFERENTLY than UHF Propagation, esp. over WATER to Tampa/StPete stations, as thermal inversions refract radio signals differently close to sunrise and sunset.
And finally, those Hi-VHF Stations MAY be reconfiguring their PRIMARY Transmitter/Antenna Systems....or trying various Signal Sharing techniques in anticipation of upcoming Channel Reshuffling and/or operating SOME Transmitters in ATSC 3.0, while still operating on SHARED ATSC 1.0 Transmitters. While they do this, the "Second Shift" Engineers may be taking over the Primary for Testing, forcing the use of the (probably lower power) Fallback Transmitter/Antenna System.
TVFool is typically a bit out of date, so fol. is rabbitears.info report for TAMPA DMA....I tried various Street Addresses in Brooksville [per Google Map], but was unsuccessful in getting a Signal Strength Analysis Report:
Note that THE CW "should" be on Ch44....if you can receive it at all from StPete. I was very surprised to see only W26DP (Ch26) station from nearby (26.5-mi) Panama City area....so I guess the Florida Panhandle isn't as FLAT as I thought.....
Since TVFool is typically a bit out of date, rabbitears report is more current and shows the upcoming Channel Changes.
It might help if you entered your ACCURATE Address and ran another "SEARCH" [check the STRENGTH SEARCH box]...and post the Results URL (Address at top of your WebBrowser).