JNFamilies are turning me into a head spinning demon.

I haven't had a chance to tell much, but between my JNfamily and DH's I think I am losing my shit. I don't even know where to turn for help for the anger I am experiencing. I had an epic meltdown in the car today, to the point where it physically affected my body because of all the shit I don't take out on my MIL who actually deserves it. Besides therapy, which I can't afford right now, do you guys have any suggestions where I could go or what I could do to salvage what is left of my mental state?