Just because some studies show proviron should make most feel better it doesn't mean it will do the same for you. Google proviron and anxiety and there are countless threads of people experiencing exactly what you are from it. Anything could make someone more anxious so it's not because your proviron must be fake. Any fluctuations in hormones can cause anxiety in people who are sensitive. Sometimes it doesn't have to make much sense either.
I can take large doses of multiple AAS and feel fine. I was ok with proviron last time I tried it but it 100% can cause anxiety. Mast can make me feel off at times. HCG is horrible for me. Tren is the worse. EQ is bad but if I move up gradually it's manageable. Test, deca, npp, primo, avar, winny, dbol, adrol, sdrol etc are all fine. However sometimes you may respond differently. An example if your estrogen gets too low that could cause issues as you know. The same for prolactin and high prolactin can cause bad anxiety.
The only advice I can give you is stop the proviron if it's that bad. If it's a 5/10 then you could lower the dose and see how you get on. It all depends upon how bad you have responded to it and is it worth the risk. Get blood work done and see how everything looks (test, estrogen, prolactin, cortisol etc).