Welcome. Sorry to hear about your accident. Unfortunately you made 2 mistakes. First, the #1 rule with sway is you
must mash on the brake controller (and don't touch the TV's brakes). Second, you never want to try to steer out of the sway - hold the steering wheel straight (within reason, steer away from traffic of course).
See the link in my signature and look for the article on sway.
The fresh water tank is behind the axle on the 177, true. However, with adjustments to apply more weight forward of the axle and to increase the sway control (which differs depending on the brand), it is perfectly safe to travel with that tank full and the waste tanks empty. My 171 has a different configuration but I've traveled most of 15,000 miles with the fresh water tank full.