A heat pad on her tummy can help a little. When she gets really agitated, sometimes being shut in a dark room can make her take a nap. Otherwise, you just have to tolerate it! And hope the next 2 weeks go quickly! Although she'll probably stop calling so enthusiastically in a week or so.
I have 3 girls and only one came to me spayed. I was fortunate to only have to go through one heat with one of the kitties, and like you we already had her spay scheduled. The most important thing to do is to be extra vigilant about making sure she stays inside. Do whatever it takes to make sure she doesn't escape, even if it means leaving her confined in a bathroom for the time you're away. What we found that helped our girl was putting her in a quiet room by herself and putting her in a large crate or her carrier if she was out and about with our other kitties. The smaller spaces seemed to help her calm down.
I recommend keeping her in a closed room, to avoid escape, and an investment in earplugs or noise canceling headphones.
Sorry... it's just part of their nature. We had to do the same thing when ours went into heat... some of the longest weeks
I once had to endure a foster kitty that came into her first heat and the yowling kept me awake for several nights in a row, that in the mornings at work I felt so grumpy and suffered from headaches. But as mentioned above, there is nothing you can do but to ensure she does not escape. And yes, a heated pad as WWillowy
mentioned may help.