i think you're putting way too much pressure on yourself. nobody plays their best when they're trying too hard.
you really are a 3.5 player. you used to be top of the rung 3.0 and now you're a freshman in the 3.5 school - suck it up. the girls are all more experienced and in the case of doubles - they will home in on the weaker player - which means you will get a ton of balls hit in your direction.
for me when i'm the weakest player on the court (which is more than i would like) - i focus on not doing too much. just solid tennis. no low percentage shots. no aiming for the lines. nothing flashy. just bread and butter tennis. make them earn points by forcing errors/hitting winners rather than me handing them points on a platter.
oh and when you play these better ladies -- ask them afterwards "if you were me, what would you work on first?" they will tell you what you are weakest in.