When is it too late to eat??

Never. It's what you eat not when you eat it....Protein will not turn into fat. Your body will just force it out.

After a workout take in some simple carbs like a banana and a protein shake with maybe some casein protein.

To give you an idea At roughly 10-12pm-1am latest I eat:

2 scoops of Whey protein
1 scoop of casein protein
1/2 cup of 0% milk
1/2 cup egg whites
2 tblspoons of PB
and 1 banana
1 cup of water

I seem to keep losing.....

Weight loss is about calories in vs. calories out; there is no scientific evidence that eating late is harmful.

I usually go to the gym after work and get home late-ish too, so I usually only have a protein drink/shake after the gym. I make sure I eat enough calories and protein earlier in the day (for breakfast, lunch, and snacks) so I can not have "dinner" and still be in range for my daily calories.

For me, it isn't that I don't want to eat late, it's that I feel sick if I have a full meal too close to a good workout. I think that you should listen to your body and if you're hungry then you should eat!