I'm known to bring a can of drink in everyday for lunch. It's kept in the shared fridge at work - Everyone knowns it's mine as there's a little section box for each person with their name on.
A colleague of mine is pregnant and for the third time has taken my drink and not bothered replacing it. When questioned, she says something along the lines of "Sorry! Bad sickness. This helps. I'll get a new one for you tomorrow".
She always does, it's there the following day. But it means having to go out at lunchtime to get another one. The local shop is only 2 minutes away but it means eating up time I don't have since I have 30 minutes lunch.
I'm really not sure how to go about it. If it was the usual person, I'd tell them to stop the cheek and buy their own to bring in! But she's pregnant and suffering from sickness. I had HG with my son so I feel awful at the thought of telling her she can most certainly never take from me again without asking 
I remember the horrendous feeling of needing something sweet and fizzy to curve the sickness and it did often help, so I imagine it's very helpful to her.
Perhaps I should buy a multipack and suggest she goes half's so we can both enjoy them during the week? Or is this too doormat like?
I'm really not sure how to go about it. I don't think she thinks she's being cheeky in the slightest, and is an otherwise lovely colleague.
What would you do? I usually have no issues being assertive but I feel as if the lines have been blurred.