whatsapp beeping problem hope you can help

I have had Whatsapp on my nexus 4 for a few months and been very happy with it. Saving me money sending photos etc.
However the past week it is beeping all the while and flattening my battery after a few hours
I usually have my phone permanently on WiFi and then when I am out it out connects at Starbucks McDonalds & other places.
However Whatsapp has started beeping & telling me I have no WiFi in between... None stop
It says switch WiFi off.
So tried that but then it beeps saying no connection!
How can I stop this and why now?