BTW, if you need help finding a low-cost clinic to spay her, please just let us know what city or county and state in which you live. You can send me a private message if you like.
Before we had Elsa spayed she was going into heat every couple weeks or so. When they spayed her, she was full of cysts all over her ovaries and inside. They were producing so much estrogen (or the kitty equivalent) that it was making her be in heat almost constantly.
From reading both of your posts, your kitty is a young female experiencing her first season. This is completely normal, they can go in and out of heat within weeks and the discomfort and symptoms of will only intensify each time. She needs to be spayed, it's the only way and the sooner the better........
Cycles vary from several weeks to just a few days, some girls call almost constantly. You need to be very careful with the amount of times she goes into heat, too many cycles can cause deadly infection.
Please take your girl in to be spayed soon as you can and be very careful she doesn't get outside.