No one can understand a girl's situation in her periods' time. She suffers from pain, the itchiness, ugh the smell and have to keep changing the tampons/pads frequently, and all this totally frustrates her, especially early stages of life after her first period. She needs extra love and care at that time (and the love can be expressed by gifting her lots of chocolates).
So guys, next time keep in mind that it's the period which is irritating her or spoiling her happy mood and try to be a little patient with her.
Just know a girl's feeling by growing through these tweets.