If you don't feel right in the gym at the momment then don't go. Instead try to aim to just go for a moderate walk around your area / beachfront etc...

Try to drop the bad foods out of your diet 6 days of the week and have a cheat day to rid the cravings!

You will be suprised and should see results from this change if you stick to it. Don't try to change to much of your lifstyle at once because you will get fed up.

Good luck!