Its because of the caffiene
I'm sorry I read your question wrong I thought you meant you could feel her after the coke...I'm 23 week and don't alWays feel mine until late at night so you should probably be fine. I have a soda almost every day
I have changed my tea to decaf just so I can have a coke or 2 a day too. :)
I'm 24weeks and drink one cup of coffee or one can coke a day and i don't normally feel my baby girl move till I'm laying down or sitting down this has been her normal movement cents 18weeks
Its fine some midwifes tell you to have a fizzy drink if you are worried and can't feel them. They don't have that much caffeine in its probably the sugar making it move.