Cat in Heat

I think my female cat is in heat I called the vet, but I have to wait until this is over. Yikes its been 3 weeks! I did get the male cat about 3 weeks ago (but he is fixed). Could this be it!

The vet thought it was odd she has never been in heat before. she was always an outside cat (a friend could not keep her) so I have no clue if she had been.

My question is: She is going nuts, when the door is open she runs upstairs (does not want to go out) which is very unusal. Infact since the male cat who has been fixed, came she comes down to eat then runs upstairs.
How long does this last?

Mother of 4 Cats all are fixed except her, 2 males one female. The male cats look at her like she is NUTS!!!

Help!!!

the best bet would probably to just get her fixed, esp if she is an is inside/outside cat. and that way you will prevent any unwanted kitties.

one of my friends cat went into her first heat last year, and it was HORRIBLE. yowling and crying for hours. :eek: