Is it worth pursuing a employment lawsuit in Virginia since is is a at will state?

I may be wrong, but I believe that every state is an at will state. Unless you have a contract (which can be an individual agreement, a union contract, or can arise from an employee handbook) which limits your employer's right to cut your compensation, or you believe that your employer discriminated against you, or was motivated to cut your pay, for a reason prohibited by statute (age, gender, religion, certain types of whistleblowers, etc.), you would not have a claim.