Here's the deal. When you gain5,6,10 pounds this early on it is water. The test , as you were told takes about 5 sometimes 6weeks to really start to effect the processing of protein to muscle. It does begin earlier but it hasn't had enough time to work in combination with your workout to be growing new, more LMM.
Keep in mind that if you don't gain a lot of weight like some young guys that's a good thing if all you workouts were good and your diet. Why I say this is because a man, after youth can only gain 15-20 pounds of LMM in one year. So when it is all said and done and your off and down and loose all the water your weight will be an increase mostly of the lean muscle mass and that's what its ll about and one of the most important reason we/I do steroids. Your strength and stamina will really begin about 5-6 weeks we are all different. Good luck......That's my 2c