<human>: I think I'm lucky I didn't get arrested for this one.

Yesterday morning I was due for some blood tests and a chest X-Ray.  My father drove me (I'm 17) and we arrived at the health center (like a mini hospital, don't know if this is just a UK thing). We took a seat in the waiting area of Radiology and I placed my college backpack down next to my chair, which was on the end of a row, pretty much in the middle of the large reception. I got called in for my blood tests and during them I felt rather dizzy. I was given water, I walked it off, it was just my first time having blood taken. I was instantly called in for my X-Ray and I was notified about this by my father who'd walked up to tell me so I could go straight in. Here's where the fuck up happens. I proceed in my dizziness to completely forget about my bag and my father this whole time hasn't even been paying attention to if I even had a bag with me. We got my X-Ray done and left, and when I get to college we realise I don't have my bag. Immediately I call the Health Center and ask to be transferred to Radiology, but nobody answers at reception. We get there and it turns out they had to call the army and I had to explain that I just-so-happened to innocently leave a suspicious, plain black backpack strategically in the center of the building. When I got back to the car my dad was in fits of laughter, and I had some guys dressed in camouflage looking at me accusingly in the car park. I hope I'm not on some list somewhere now...

Give me the gist of the text in a nutshell
<bot>: went to get blood tests before college, left my bag in reception, had to apologise profusely to the bomb-squad.