Urea level slightly low

Hello my family,

Hope you all had a great Christmas, and got all you wanted. I got some of my blood results back today, my cea I wont get until Wednesday. Everything is ok, liver, kidney etc, apart from urea which is just slightly out of range being low. I was ill for a few weeks with stomach viruses, gastritis, then flu, and I was on antibiotics. Could that have anything to do with it? Doctor is not to concerned and wants to repeat blood test in 4 weeks time, but as some of you know what I'm like, just worried slightly, hope my cea will be ok.
Oh btw started taking probotics today
Hugss to you all
Sonia