<human>: Could you distill the essence of the text into 1-3 sentences?

sorry for the vague title but I didn't exactly know what to say without it being too long. yesterday I was at school in class. nothing out of the ordinary. but then out of nowhere this cleaner comes in with a gas mask and starts spraying what I think was carpet cleaner on the walls (the walls are covered in carpet). mind you this was in a room with no ventilation what so ever. no vents, no windows that you can open, nothing. this went on for about 10-15 minutes before our teacher finally decided to go up to the guy and say to stop it because it was 'disrupting us'. we all felt drowsy/sick while this was happening and I almost feinted. we ended up moving into another room. i ended up going to bed when I got home. and i woke up with this really sore throat. I just spoke to my friend who was in the class and he was saying he's been having stomach problems since he got home. There has been a bit of a cold spreading around as of late so I'm not sure if that's what I'm currently experiencing. Now this wouldn't be worrying me AS much but I was also diagnosed with leukaemia at the end of November last year. If I get sick, even if it's just a cold I'll have to be hospitalized again. I'm started to get pretty scared at the moment because if it IS worse than that I don't know what will happen. I tend to worry about nothing when it comes to these sorts of things. I'm contemplating the worst at the moment. Am I just worried over nothing? what should I do?
<bot>: went to school, cleaner sprays carpet cleaner in the room, might be really sick, also cancer. what do?