Hey Phil10, it's my second bout with DP/DR. I recovered from my first one years ago and during that first bout I had the same struggle as you are describing.
Trust me, it will go away.
I used to have panic attacks just by thinking about the concept of solipsism. I once had to leave a family diner because the thought "am I the only one and is everything else fake? Is this the matrix?" crossed my mind. I went back home and started crying in room. It was as bad as you can imagine.
NOW, would you believe me if I tell you that 6 months later I was perfectly fine and watching the Matrix Trilogy laughing my ass off with a pack of pop-corn in my hand? That's the actual truth.
And the more important truth is, for you AND for me (for people in DP/DR states), our Fear centers in our brains are on RED ALERT and they are looking for any thought that would freak us out. For you, it's solipsism and the absence of free will as it was for me back then (currently, I couldn't care less about absence of free will cause I know I 100% vanquished that fear in the past so my brain is now focused on another scary thought of mine).
So keep in mind that it will go away when your anxiety level will drop back to a more normal level.