Hello,
6 months ago I found a cat outside during a storm and brought her in to keep her safe. I took her to the vet to locate an owner via micro chip but no one ever contacted me, so I decided to keep her. Over the past 3 weeks she has been displaying behavior of a cat in heat, such as yowling, excessive meowing, tail to the side, butt in air, bodily response to "mounting," and being overly affectionate. I took her to SNAP to get her spayed two weeks ago, but that's when I found out she already has spay markings. I took her to the vet again a few days ago and I paid $60 for them to tell me that they don't know what's wrong, and other than an ultrasound they can't really do anything. I paid for some medicine that's supposed to calm cats during flights but she either won't eat the food it's in or she doesn't even respond to the medicine. Her meows are not normal. She sounds as if she is in distress and when she isn't making the baby-crying sound, she is literally screaming at the top of her lungs. She just sits on the floor and screams hysterically. The only thing that keeps her quiet is petting, but I don't want to reinforce this behavior. She does this all day every day and at all hours of the night. Please help me. I don't want to give her to a shelter or put her back outdoors, but I really don't know what else to do. Thanks.
6 months ago I found a cat outside during a storm and brought her in to keep her safe. I took her to the vet to locate an owner via micro chip but no one ever contacted me, so I decided to keep her. Over the past 3 weeks she has been displaying behavior of a cat in heat, such as yowling, excessive meowing, tail to the side, butt in air, bodily response to "mounting," and being overly affectionate. I took her to SNAP to get her spayed two weeks ago, but that's when I found out she already has spay markings. I took her to the vet again a few days ago and I paid $60 for them to tell me that they don't know what's wrong, and other than an ultrasound they can't really do anything. I paid for some medicine that's supposed to calm cats during flights but she either won't eat the food it's in or she doesn't even respond to the medicine. Her meows are not normal. She sounds as if she is in distress and when she isn't making the baby-crying sound, she is literally screaming at the top of her lungs. She just sits on the floor and screams hysterically. The only thing that keeps her quiet is petting, but I don't want to reinforce this behavior. She does this all day every day and at all hours of the night. Please help me. I don't want to give her to a shelter or put her back outdoors, but I really don't know what else to do. Thanks.
Welcome to TCS! That is certainly odd behavior! Did the vet explain what they would be looking for in an ultrasound? Alternatively, your vet might be able to administer hormones. I know that my vet can give the feral toms a shot similar to the human birth control pill; this shot helps the toms calm down and quit spraying as much (sometimes older toms seem to get a brief spike in hormones right after neutering & create lots of havoc before retiring from their tomcat ways). It might let your cat's body think it is pregnant. 
Ouch! I am sorry that you had to pay $60 with no results, too. And your poor cat and you - the situation must be nerve wracking, to say the least. 
The caterwauling is definitely annoying. I wish that I had a better answer for you. Please keep us updated! Any answers that you come up with can be very helpful education for the rest of us! 
