NU 2L now, I essentially made the same choice you did a couple years back. I had the same scholarship offers you now have from NU and WashU (plus a slightly smaller offer from Mich). Obviously, chose NU. Happy with my choice, but obviously have no idea how WUSTL would have turned out for me. To me, NU is worth the extra money. The opportunities, the better network, being considered in the top tier of schools... to me they're worth more than the extra debt was going to cost. tbh, I haven't found NU super stressful either. Put your head down, do your work as a 1L and you should end up in the top half of the class without issue, and you'll be able to feel pretty comfortable going into OCIs.
Also, NU attracts a fair amount of transfers from WUSTL every year. Not sure if they're eligible for scholarship dollars, but might be worth looking into if you're really concerned about too much debt.
PM me with specific questions-- it's hard to give really specific advice when I'm not sure what your primary concerns might be. I also might be willing to divulge more info about my situation than I would in the public forum.