First of all beating yourself up over missing a meal is not going to help, as it creates stress for yourself, never gain any weight if your stressed. 4 day split is fine, optimum is 5 with 2 rest days. What kind of rep sequence are you using, how many sets per bodypart, need some more to work with. As far as gaining, again I can't stress enough to try the shake in the middle of the night, look at it this way, your body is geting no food for at least 8 hours so it starts to burn while you sleep. If you give it something else to burn such as a shake then it will not be burning what you already have in the middle of the night. You follow me?
it this true?? should i go back to a five day split??
thx