i average about 7lb in water retention but everyone is different, it will balance itself out. Try not to worry about what appears to be no weight loss. a week afterwards it will all show up.
Rybens the mirena coil? if so then that should sort you out, can take about 3 months to settle down, and if your lucky they will stop totally. I had 10 years with them that has made a massive difference, i was finally able to leave the house during my TOTM. Good luck