Everyones body reacts differently to every AS out there on the market, just because Bob from down the road got the sustanon flu, it doesn't necessarily mean you will also.
As for switching, I'd recommend that you finish this sustanon cycle which you've already started.
'I'm not sure the
sust does it for me'
If you're only in your first or second week, you won't really see gains off the
sus or feel its effects until 4weeks + seeing as unlike other testosterones, sustanon is made of 4 esters and is a slow release form of testosterone.
IMO, I'd run it for 8weeks @ 500mg EW.
This is just my advice.