My dd (20months) is very sensitive, and can be easily upset by people and situations she is unfamiliar with. She is also afraid of the vaccum cleaner. Generally, I leave the vaccuming to dh, because of this. But one day she tipped over the litter box and made a big mess which I didn't want to leave until later. She freaked out when she saw me get the vaccum cleaner. This is what I did: I gave her a 12C dose of Pulsatilla, a homeopathic remedy based on dd's own constitution (or, you could say, personality type). Then I read her a book to give it time to work. Then I vaccumed with no problem whatsoever!
Another time, we were visiting at my midwife's with other ex-clients. It was crowded and there were lots of little kids. After a while, dd became overstressed and was practically freaking out. So I gave her a dose of Ignatia homeopathic, and a few minutes later, she had calmed down.
I got my information from a book called The Family Homeopath by Robin Hayfield. Homeopathics work for physical problems as well, but I think they've been a life-save for emotional issues. Some people have great things to say about the flower essence mix Rescue Remedy for emotional upsets. I use RR when dd is upset by a fall or something similar. But I feel the homeopathics work better so long as they are used by someone who is properly informed.