30 Day Shred Question - final results after initial gain?

Hi, I've been doing Jillian's 30 Day Shred (today is Day 9) and it turns out I'm one of the few whose body is experiencing a gain instead of a loss. So far, I've gained about 5 lbs (half of what I've managed to lose since beginning May), and I'm trying my hardest not to freak out and give up. Instead, I'm hoping that someone can give me some thoughts about their experiences.

In terms of measurements, they haven't budged much either way - with the exception of my legs, which got bigger. My calves are huge right now (they've gone up by almost 1.5 inch) and they're pretty hard - so are my thighs. My legs and hips have always been my problem areas, so I'm quite disheartened by the increase as they definitely don't need to be any larger.

I've read around and am well aware that some people go through an initial gain period. I also understand it's likely not muscle either, as muscles don't build this fast. It seems the general consensus on an initial weight gain is due to water retention in the muscles. I'm really really hoping this is the case, as it gives me hope that this additional weight will drop off eventually when my muscles get used to this.

I can't seem to find much info on the final result for those who did gain at first. Most have such fantastic results with the 30 Day Shred throughout, and the few who gained seemed to give up on the workout so I'm left wondering what the final verdict is for those who went through the same thing I'm going through after sticking it out to the end.

My questions are (if anyone can please please help me answer them):

1. Can water retention cause a noticeable increase in measurements? Could it be the reason my legs are bigger right now? How much can one really gain from just water retention?

2. For those of you who have experienced a gain doing the 30 Day Shred, how much did you gain initially and how long did it take for that to drop back off? And when/if it did finally drop off, did you lose any extra weight on top of that or were you right back to where you originally started? Or worse, are there any of you who never did manage to lose that initial weight gain at all throughout the program?

Please do excuse the lengthy post - I'm doing my best in not giving up, and with the scales climbing up and my legs getting huge, it's getting difficult! I love the workout and I like that it helps me get stronger and toned... but now I'm wondering if this is the right time for me to be doing this. Perhaps I should wait until I lose more weight before attempting this? The amount of weight I have to lose isn't much, so I'm well aware that it'll be difficult to lose them to begin with.

Some additional info that may help:

Age: 33
Height: 5'3"
SW: 140-141 lbs
CW: 132 lbs (I was approx. 127 lbs before starting Jillian)
GW: 115 lbs (dream weight: 110 lbs)

I don't keep my food diary here, as I was already previously using something else on my desktop computer to keep track. My calories intake varies day to day, but average out weekly to about 1200 per day and I've been eating healthier than I've ever been my entire life. Before 30 Day Shred, I was losing approximately 1 lb a week (not much, but I wanted to do it the healthy long-term way) so I know it isn't my diet that's causing me problems as I was doing just fine without 30 Day Shred.

In terms of exercise, I work out on average 4-5 days a week (until the start of 30 Day Shred, then it's been every day since). I do a variety of stuff, from walking, jogging, Leslie's WATP, Jackie Warner's power circuits, Zumba video, and intervals on the elliptical at the gym, so it's not like my body isn't used to some exercise. I drink more than the suggested amount of water every day, etc.

I'd really appreciate it if someone can shed some insight or share their experiences with me. If you did gain, what was your final result? I like and do want to build muscles, but I want to be smaller overall as well... not bigger. Please help!