Hi Sweetie!

I'm not sure what to tell you. It isn't about time for your period, is it? Have you been drinking plenty of water? I know it sounds crazy, but one of the best things for water retention is to increase your water intake. You could also try some Taurine or some Asparagus extract tablets; both are good for relieving water retention.
It's fairly unlikely that the protein you've been eating is causing this unless you have some underlying medical condition that you were unaware of before you started. Low carb is more about high fat intake than it is about high protein intake even though the protein amounts aren't limited.
If you're very concerned about it or it doesn't start to clear up in a few days, a trip to the doctor may be in order.
Let us know how you're doing.