Call UA and ask for mercy.
If that doesn't work and you're worried about being stressed when going from DCA -> IAD (I personally think you should just uber and not be worried about it since the toll road is amazing) then now would be an excellent time to sign up for that free month / 3 months of CLEAR if you haven't

Get you through that TSA-Precheck line like nothing! Although I've never had to wait more than 2-3 minutes in pre-check but I am not based out of IAD so I defer to [MENTION=793957]dcfromdc[/MENTION] judgement.