Muscle Gain, Weight Gain, Water Retention

I am almost a year post RNY and about five pounds from goal.  I have been working out consistently since eight weeks out.  I am testing for black belt in four weeks, after five years of training.  I had a month long stall in December on weight loss, then I lost eight pounds in January when I started doing 2 a day workouts four days a week and one on Friday.  (Increased my cardio and kept my weights at 45 minutes a day with trainer.)  I consistently eat between 1500-1800 calories a day, I am 5'10 and I my weight last week was 160.2  (lowest yet.)

I gained back  eight pounds seemingly overnight.  It dropped down three pounds one day, back up the next, and now I have been sitting at five pounds gained for about five or six days.

It isn't muscle - obviously I didn't put on five pounds of muscle overnight and my scale says I have LOST muscle mass and gained fat mass.

I know your muscles can hold water when you are training hard. Is this a possibility?  5-8 pounds worth?

I am not freaking out, really - but I do want to get to goal weight, and this is the first time since surgery I have gained weight that isn't a one or two day water fluctuation of a pound or two.

Thanks for any advice.  I read here all the time but rarely post because my connection is so slow.

Training hardcan cause that. To keep you sanity make goals about speed or strength not so much about the scale. Weight is only a number !

Thanks.  That was my goal with increasing the cardio and the two-a-days on the workouts, I am just still a bit paranoid about the scale.

Seemingly (again) overnight, six of the eight pounds have disappeared, so I am going to assume the rest will too.

i concur w/nate. i never was a scale hound. only weighed in on doctor visits. just go by how your clothes are fitting. it has been the best indicator for me.

I am trying hard to get to that mentality.  I am scared of weight "sneaking up" on me, even though I know I am doing all the right stuff.