On TN for "mo fault" divorces there is a 60 day waiting period after filing and 90 days for an "at fault" divorce.
You filed in March, so if it is the former, you're at about the 60 days. If you filed the latter, you have about 30 more days.
Before you proceed, I suggest you write the lawyer for a status update. You could check with the court clerk in the county where this was filed for a status update.
If you get no answer, sure you can begin again in another state. The problem with that is the new state normally has a waiting period. In TN one had to have been a resident for six months to file for divorce. In other states, it can be as much as a year. In some states, you have to had lived for so long in the county where you file.