Sustanon at 250mg per week is a pretty low dose. I would increase that to a minimum of 500mg per week.
If you are in your 20's, that dose probably isn't much higher than what you're pumping out of your nuts anyway, and once you introduce that low dosage and turn off your HPTA you'll stop producing any of your own testosterone. There won't be any increase in side effects from an increase to 500mg over 250mg, anyway (unless you want to call getting huge a side-effect
)