If you only ate 30 grams of protein in the morning,and weren`t hungry until the next day,then you should have eaten whether hungry or not because 30 grams just ain`t enough.
That being said,I don`t think that you should eat by the clock anymore,like say the dogma of every 3 hours or you`ll turn into a fucking pumpkin ( I used to believe that hype though),so I say just make sure to get your required macros in per day without eating the meals too close together of course, so as not to cause digestive overload.
I do try to go by the "eat when hungry" adage these days,but if I`m not close enough to my macros,I just eat something that brings me close enough to where I need to be.