<human>: Can you condense the text into three sentences or less?

So two nights ago I had a group of people over to have a bonfire, a few of my friends took mushrooms, I had just smoked a little weed and had a beer or two. 
When my SO arrived with two of her friends she seemed slightly peppier than usual but I didn't think much of it, we walked to the fire hung out for a bit then everyone came back to my house once it was out. 
When everyone left it was just the two of us and I noticed her pupils were substantially more dilated than usual (one of my friends commented on this the next day), I asked if she had smoked at all and she said no, I asked her if she took anything else and she said no and then asked why I asked. When I told her it was because her pupils were huge she said, "oh no my pupils are just big sometimes" (something I have never noticed before) in a slightly unconfident tone. 
Its important to add that I have taken many different substances in my life and am in no position to judge someone for what they use/take and she fully knows this. 
Trust is something I've always struggled with in relationships, and it doesn't bother me that she took something, but that she wasn't honest with me about it. 
Keep in mind she leaves for college in two days and we aren't staying together past then. 
So my question is should I confront her about it or just let it go?
<bot>: I think my SO lied to me about being on something and it's making me question my trust toward her, do I confront her about it or let it go because she leaves for college in two days?