Vet traumatized kitten

I have a three month old kitten that I rescued when I found her mother dead. I brought her into the vet for the first time since she was less than a month old. She used to be so great with new places and animals but now she hisses and growls and spits in fear away from them.

Given her already being stressful from seeing the other cats, when the vet saw her she was in full on defence mode, showing so much aggression (more so out of fear. only strikes when approached). he had to do his stuff and give her vaccines, cut nails, give dewirm and exam. The entire visit was her growling and hissing and scratching and biting, and he was handling her most of the time, constraining her and holding her in ways that she couldn't move, lots of scruff holding which just made her worse.

since she's been home she's been cowering away from people, hiding under beds, very lethargic. Whenever I touch her or go near her she gets very aggressive, hissing and scratching and biting. She had never shown aggression inside the vet before and I'm Hoping for advice to help get her to trust people again.

Do you have any feliway diffusers?  This might help.  Also play therapy is very useful to help cats regain confidence and feel more secure and happy.  Try the process of hunt, catch, kill, eat, groom sleep.  Get a feather wand toy ( da bird are awesome) or laser pointer and really get the kitten active.  It may take a bit for her to not be afraid.  If she is afraid of the toy, try a shoe string.  Just really try to get her active.  After a really good tiring session, reward her with a special treat or small meal.  This will satisfy the "eat" .  If you played enough to tire her out and gave her a snack, she should then groom herself and take a nap.  You can do this exercise a few times each day.

How long has it been since you went to the vet? 

I would do my best to block off hiding spots under beds and under furniture.  Instead provide her with a hiding box that can be a simple card board box with a cozy blanket or even a hiding box of a cat tree near a window.  You want to gently force her to be out from hiding.  You might want to take the bed and place it directly on the floor as blocking it off might be really hard. 

Also try to spend as much time with her as possible.  Use special treat rewards to your benefit.  Try plain cooked chicken, small pieces of canned tuna or salmon work well too. 

Two things come to mind, both just based on personal experience: give you cat space for a few more days. Try to keep to the routine you had before this incident. Don't shower her with affection just because she is upset. Instead, I'd allow her to do what she needs to do and try to wait her out. Often the more we do to comfort our animals, the more confused the animal becomes.

My second thought is, if at all possible, get another vet. I went through a number of vets before finding the one I use today. We have a small farm, so we have small animal vets and large animals vets. My cat/dog vet is fantastic! Because we also do some limited rescue work, I often bring in traumatized animals. I never cease to be amazed at how these animals often relax in my vet's presence. They may be very anxious around people at home or in the office, but as soon as the vet comes in, the animals relax. Over the years he's taught me a lot about how important human energy is, especially for stressed animals. After having a very bad experience (similar to yours, but a bit worse) with another vet and a very anxious cat, I took the same cat to my now vet and the cat acted very different. Good vets are sometimes hard to find, but they are worth the search.