Crikey, where to start.
who told you split set-ups are more effective?
You wrote; "Diet stayed like shit and had to take roughly a month off gym, going on the occasional when i could fit it in".
Actions verify priorities...your first task is to think about; how serious am I.
if you did some reading you would empowered to do something about this, there is one thing that you can control in life, that's health and how strong you want to be.
You know that a very effective workout can be done in 10 to 15 minutes?
I would go as far to say that it is even more effective than your standard workout, but it's brutal and tough.