You have no idea what you are doing, right?
"I want to get big just not genetic freak big."
From what you say, your diet is/has been shit. Your training is shit. You have no idea what your real goals are and, whatever they are, you are not willing to start today, but on Jan 1st. The "fail day" for all things resolution based.
Here's what you do.
Start now. Right now. You don't need AAS. You don't need deca "for your joints". You just need to get off your arse and start training hard and heavy, eating right and getting 8 hours sleep. Maybe difficult if you are on shift work as a fireman but no more difficult that most of us.
If you can't do that and make gains NOW then you won't have your issues sorted by some magical drug call Deca or Test. You can get the fit and healthy "I go to gym" look pretty easily without the roids. And keep it. Or you could just go your way, looking for a shortcut and end up frustrated and sick cos the only real road to success is the hard road.