i dont know where you were waiting on 395 (i.e. just near the exit you wanted or near Pentagon City). i think some directions say take penn ave exit, some say 6th st. SE. but if 395 wasnt backed up to say Pentgon City. once you get over the river just try to take any exit, go a couple of blocks north to independence, turn right (east) and take it to the stadium. famliarize yourself with the grid system though in case you get lost.