crossfit/mass coexist?

[reservetech]

Question for you experianced crossfit people. I understand that the mentality of crossfit is to strengthen the whole body, cardio and anero. I have followed the program for about a month now but I seem to be losing some muscle mass. This is disturbing to me because work hard to keep myself larger than my ectomorph frame naturaly allows. My question then becomes, has anyone had sucess with a crossfit AND weight training program (along the lines of high weight/ low rep for mass) and still avoided the overtraining. If so please direct me to this info.

P.S. I eat at least 3000cal/day (w/ a macro breakdown of 40%pro 30%carb 30%fat) being 5'6 160 10%bf (so nutritionaly I think i'm ok)