Tantrums

Ally has started to tantrum more regularly.  I hate them!  She melts down at the slightest sound of, "No" and she can go on and on.  I actually get headaches from her screaming.  Yesterday she didn't want to nap and she wailed for an hour and a half.  I kept going in and trying to calm her down but I didn't want to give in because nap time is important and well *I* need nap time or at least quiet time.  The worst thing about tantrums is I don't know what is the best thing to do with them.  I don't want to encourage the behavior so ignoring makes sense but I also feel that if I just cuddled her that then I could help her to gain control of her emotions.  I also get really wound up when she is acting out and I then have a hard time controlling myself and not yelling at her.  I have no patience when it comes to the whining and carrying on.  I need to learn some because yelling has no effect on her so it just makes me feel worse.