weight loss and bounce back??

I was lucky enough to be down to my pre-baby/post WLS weight only 2 weeks after giving birth to my daughter. When she was one month old, I came down to visit my family here in Texas. I've been here for 3 weeks and have gained 4lbs! I am so scared to keep gaining. I don't know what to think. Is this like a bounce back? Is it normal for us to gain weight after giving birth? I really hope that it's just the horrible eating i've been doing during this trip and that I am able to stop the weight gain and re-start the weightloss ASAP. I think I just need some reasurance and encouragement and advise on how to go about doing this again. I had been at a stable weight for about a year before haveing my baby and the post pregnancy weightloss was pretty effortless so my head hasn't been on weightloss mode for a good long while now but I know I need to change that quickly before the weight gain gets out of hand!

 You and are almost surgiversary buddies (1 day before yours)  When I had Alex, i had the initial loss and then regained about 10 lbs as well.  I'm still above my pre-pregnancy weight (I was underweight when I got pregnant) but it's coming back down and am now about 5 lbs away.  Everyone keeps telling me "it took 9 months to put it on.. blah blah blah".  I think our bodies just respond with the hormone fluctuations after giving birth and that lasts for months.