What could this be?

[123456thu]

2 year old got some sort of sick bug 3 weeks ago, sick all night then horrendous diarrhea for 5 days. she was fine for a week then Saturday night she was sick, Sunday night sick, Monday sick at night and diarrhea Tuesday day and sick in the night screaming in pain with a stomach ache. She's not eating or drinking much today but seems ok in her self. Obviously I'll have to take her to the doctors if she gets dehydrated.. but can't ideas why this sick bug has come back?
We haven't been out virtually anywhere to catch another sick bug.
My husband had bad stomach for 5 days, my son had diarrhea for 2 days then sick once. And my other daughter was sick once and nothing else.. but that was all within the first week that she was ill.
Any ideas?

Going around in our house too.

3 of us had the flu 10 days ago, and in the last few days the 2 littlest have had vomiting and diarrhoea.

Apparently flu and norovurus are ripe at the minute, and obviously kids are very vulnerable if they've not had exposure before.

It's awful isn't it. Absolutely hate sick bugs. It's just weird that it's come back again for her.
I'm down so many sheets, pillows, towels and duvets from sick. Lol

Oh my God, same here.
I did 5 loads yesterday and we still have more to wash!

Something weird going round this house too. Adult son sick three times last Monday and then fine. I was sick once Weds night and then fine and my youngest was sick literally every twenty minutes Saturday night and Sunday. Fine all of Monday and then sick three times Tues morning. Fingers crossed seems Ok so far today.