Probably stupid but freaked me out

A few months ago I was having problems with nausea so went to a pharmacy to buy some over the counter anti-nausea pills. I have a daughter so when I got home I took one and then put them really high up in an empty built in wine rack, high up enough to ensure that there was no way my 2 year old to get to them.

Later that day my sister called to ask if Iwanted to go to the cinema but I was worried about feeling nauseous again later so quickly grabbed the box of pills from the wine rack before shoving them in my pocket and leaving. We went to dinner and I started to feel a bit sick so reached into my pocket to get the packet of pills, opened them to find that there were only 2 pills left when there should have been 9! I just cannot think of an explanation for this...there is absolutely no way that my daughter could have gotten to them, I didn't pick up a different packet becauseI went home and searched everywhere and didnt find any different packs, no one else had been in the house in that time so they couldnt have taken them...the ONLY thing I can think of is that someone had taken some before I bought them but they were behind the counter and I hadn't noticed the pack was partly empty when I opened them to take 1 pill earlier in the day? Like I said, probably stupid but i just cannot really come up with an explanation for it. I also checked my pockets to see if they somehow came out but they were empty.