I would at first check the obvious...like is your tranny fluid level ok? Does it smell burnt? or have you tried it in another gear to see if it moves? Seems like it could be tranny related...take a look at those things and report back what you find. Whats your mileage and have you had regular tranny flush ect...those things will help better diagnois the problem your having. Always seems things go bad just when you think they cant get any worse.Sorry to hear of your problems...but let us know what you find, and maybe someone can advise you more.