I gained weight?

What the heck. I stepped on the scale yesterday to discover that over the last month or so I had gained 6 pounds. I've been eating well, training hard. Perhaps some is muscle but really I was not happy to have gained back 6. At one time it seemed pretty simple, now it just seems that there is a lot of conflicting info about calories and training. I might track my eating for a bit too, make sure I'm not sabotaging myself somewhere and just keep training. Hopefully that will make a diff. It's funny too cus I was feeling quite pleased that I was starting to get some ab definition. (Big deal after 3 pregnancies) Otherwise Training has gone well.

Summary:

T- 60 min ride and interval swim training. Dis 1250m Shorter swim than planned due to
irritable daughter syndrome. C is 11 and she often comes to swim lengths with me. Her
shoulder was sore (bball provincials on weekend previous) from pitching. She kept
piddling around getting in the way. I wasn't feeling as well myself.
W- morning spin class. eve 60 min run. Had to run in the pouring rain. It was pretty warm
though.
Th-Planned on a long swim, in the end only did 1500m swim. Went at a different time not
realizing that there was only 1 lane. Sooooo frustrating. I can deal with one recreational
breast stroker maybe even two. But then add a aqua runner and backstroker weaving all
over the lane and I just though this is dumb I can't deal with this anymore.
F- Brick workout consisting of 45 min bike and 30 min run. I really enjoyed my workout. I
actually went much faster than I usually do because I was pressed for time. I still
haven't experienced the tight legs that I've heard characterize a brick work out but I'm
not biking all that far and I'm somewhat forced to do a mini transition between bike and
run. I can't leave my bike out it would be stolen so I have to bring it in and then I switch
shoes and have a quick pee break then head out for a run.
S- Finally a good swim. total dis 2500m