I think you need to ask yourself why you wanted to be a flight attendant in the first place. Write the answer down and read it aloud. Ask yourself then, is my heart saying this is true? You can never lie to yourself you will know. Your wants and likes might have changed through the years...
If you can take a week or two off do it and see what you think then. Give yourself time to reflect. Will you miss the people you work with and the work you do and the lifestyle or are you happier on the "ground"?
Try to see what aspects of the job you like most and which you hate. What is it that you hate. Again write it all down. Is it the customer service, flying, life-style. See if there are any other jobs out there which involve something you love and not the stuff that you don't like.
You could also see a psychologist. Maybe it's not the job that you hate but something totally unrelated, some "unfinished business".
Always remember you're not alone, there are always people that would love to help you, you just have to ask.
You will be fine! Take care!
Neti