JOE, personally if I were in your position I would be really damn pleased that it is working so quickly. I think you are taking a pretty moderate dose... how did you come up with 600 sust?
Original poster, you shouldn't be seeing much out of the ordinary in terms of gains, size or strength at this point. If you don't see/feel it after week 5, then there may be reason for concerned.
Just make sure that you are eating lots of everything, and training smart, and you'll get there with or without the help of the gear.