Missed a Long Run, what should you do?

This weekend I was to either do 12 again or hit 14 depending on how legs felt, but on both Sat and Sun this weekend I kept getting dragged into meetings and annoying immovable items, and never had time to lace the shoes up for the run. It’s Mon now and I’m not sure if I should shift my training around to get the long run done either tonight or tomorrow, or if I should do more cross training, or increase the milage on my other runs, etc.

First marathon and don’t want to screw my body up doing the wrong thing. Pls help, and thank you to the awesome community in advance!