In the Heat of the moment

Oi! We have our hands so full I think we both feel we are about to start using our feet too!
As though intense kitten care were not enough Diva has now come into heat and is going mad!
She started crying a bit yesterday but I thought it was because the ground was so wet and she was battling to find a dry spot to do her business. I followed her with the litter box to no avail. She did seem to calm down eventually and I didn't think much more of it until she managed a magnificent high jump out of the kitchen window last night. She seemed determined to get out! I quickly went out and retrieved her and saw Rocko the neighbour male waiting there too so she was swooped up and taken inside and kept in all night. This morning she is so out of control and I noticed she is almost lifting her posterior at our male, Budda, who is thankfully neutered and rather confused by his sisters behaviour. Casper is mortified and stupefied by her and is hiding away in the garage! I called the Shelter Owner and the Vet who all confirmed she is on heat by the sounds of her behaviour. I also noticed a slight discharge so that is now proof positive.
Poor little girl. I have booked a spaying for her for tomorrow at the animal hospital who is open 24 hours just in case my Vet cant help in the morning because this needs to end and soon for her sake and ours.
I am trying to just stroke her and soothe her with my tone of voice but nothing is really helping. I have never experienced this before as any female I or my family have ever had has been spayed before coming into season and so this is quite hectic. I've been putting it off until June as she would then have been 6-7 months old which to my knowledge would have been perfect but the shelter now say they could have got her age wrong if she was malnourished and very small when she came in and she could very well be 6 months already.
Well just great and thanks for that!
I usually adore Sundays and wish for them to linger longer but right now I just want Monday to come so Diva can get out of her groove!