mostly water weight, the mix of the roids + creatine, ur retaining every ounce n drop of water. Your getting bloated, at best a few lbs. of muscle. Dont worry bout estrogen levels, your dr. didnt prescribe you anything seriouness enough to effect those lvls were you would even notice, mainly estrogen just cause man boobs, estro block or something if ur really scared, but as stated, no worries there.