Abs and water retention?

firstsip

Okay, so I'm roughly a week and a day outside of my period (so only a few days outside of official "PMS"), I did eat more sodium than I normally do yesterday, and I also did a hard enough work out/strength training session that I feel it in my arms/shoulders.

I've been really working my abs (crunches, dolphin kicks in pool, lower leg lifts, and planks), and I took my measurements today. Not only am I up 2 lbs (which I may attribute to overall water retention, just because of my sodium issues the last day or so), but my waist/underbust measurements went up an inch? Nothing else increased, and in fact I lost .25 inch off hips, arms, etc.

I always here people having issues with water retention from lifting or strength training--can your abs retain water, too, from being worked?