Agreed - good for you for pinpointing an exact time of difficulty. Now for the rest. What is it about the time that is difficult?
I'm not sure if this is your case, but 5:30 can be difficult for many people because they're getting home from work. A few things that help are:
-having dinner ready to just heat up when you get home
-having a snack before you leave work
-chewing gum on your way and into the house until dinner is ready
-changing your workout time to around 5:30
-eating less during the day so that you can eat more substantially at night
Once you figure it out and implement some changes, I'm sure you can do it.