Go back to basics mate. Just reset everything and start again. When I was having bad runs I used to go to the range and start just hitting balls with my feet together, which get balance right, then slowly open gradually until you feel your fully balanced and aligned.
Also break swing down when practicing, backswing, wrist break, pause at top, then follow through.
Both help me to get myself settled again.
Im doing a drill just now with resistance bands, mimicking the back swing and follow through with resistance to build a little more speed through the swing.
Last week I burst a couple of drives that were both 280+, biggest was 293 which for me and my mechanical spine is pretty good going.