I'd check the hose inlet connection...there's a screen washer that sometimes get debris in it. Also, you mentioned recently changing your water filter. I used to get super efficient inline water filters...found out that they really dropped my water pressure. The only other thing I can think of is maybe the inlet check valve maybe malfunctioning.
Bob and Debbie (both retired) with Senior FurBabies Grizz (a German Shepherd mix) and Bailey (a Lab mix)...and sometimes a Grandkiddo or 2! Full Time RVers since July 2013 Redwood: 2012 36FL with sliding patio doors
Tow Vehicle: 2011 Chevy Silverado 3500 HD with 6.6 DuraMax Dually