If not the dependence of your parents on your, then the negativity will. The drain of the area you are going to will also pull it from you.
You will not do anything without energy.
You want to do know how to avoid this and the painful, guilt-ridden answer is: You don't go back home, you move forward with your life.
You have to do it with a clear mind and a firm commitment. If you cannot move forward without feeling pangs of guilt pulling you backwards, then you aren't ready. If you can make a firm, confident decision that you:
1. Love your parents.
2. Realize you cannot change them or improve their lives FOR them.
3. Want a better life for yourself.
There is no more to discuss or mull over. It is time to hug and kiss them, pack up your bags and move to a city that will spark that fire inside you again and fill you full of hope and joy.
Your parents love you. They are probably adamant for you to NOT come home because they know, deep down, what it will cost you.
I think you know all this already, you sound smart and in-touch with your feelings. You were probably hoping for some alternative information where we suggested ways for you to help them and feel like a great son and get back on your feet and get married and have a family and not have to move back to the middle of no where and and and....
All of that takes energy and you aren't an endless well of it. You MUST pick what you direct it at and it can't be everything.
If it makes it any easier, you being home, feeding into the negative-loop-cycle your parents are in right now and becoming more depressed helps NO ONE. It doesn't help them and it doesn't help you.
You aren't a bad son for wanting happiness in your life and that happiness NOT being from taking care of your parents.
Hug and kiss them. Call them often. Send them cards. Help organize a stop-in assistant twice a week. But do all that from a location that fills your life full of possibility and happiness.
Don't bury yourself in guilt, that is a trap. Move forward. There are great things waiting for you.
EDIT: I just read a lot of fantastic feedback here, some of it the exact opposite of what I wrote, so take everything I said with a grain of salt and go with whatever feels the best to you. Whatever explanation made you feel lighter, free-er and happier when you read it and just "made sense", that is probably the one you should go with.
I am tempted to erase my comment as I feel you have so much good advice here I don't want to just add conflicting noise. Either way I'm rooting for you man, just stay in one piece and keep your head up!