Note: health concerns should not be dismissed out of hand. Since some other existing answers focus on possible urinary tract infections and other health issues, and since you have mentioned that you already visited the vet, I will attempt an answer focused on changing a cat's behaviour.
As far as I can tell, you are doing what is needed. From what I can recall from the literature and from my own personal experience, it takes at best 10-14 days of continuous behaviour (from you) for a cat to form a good habit or break a bad one. After that period, the cat should start adopting the behaviour you seek, or stop doing what is bothering you.
In your case, that means that you should ignore your cat at night for at least 10 straight nights, possibly up to 14. You should not acknowledge your cat's behaviour, you should not even acknowledge her existence at night. Act as if she simply does not exist. If she wakes you up, do not scream at her, do not complain, try to not make a sound or eye contact. Even bad attention is attention and would promote the continuation of her behaviour. If this is not something related to her health, your cat might be acting up simply because she feels like she's lacking attention.
To counter this feeling, be sure to dedicate time to play with your cats, to pet her if she enjoys it, and to generally give her attention. This "cat time" should be during periods of the day when your cat is active and ideally would be the same time every day. This will help create a good habit as the bad one is discontinued. Do not simply play with your cat every time she asks for it, that would be sending the signal that she will get attention whenever she asks for it. Lastly, try feeding her before bed: this will start a cycle of eat-clean-rest and she should go to sleep soon after. Also, you might try feeding her not immediately after waking up. That way she will not associate waking you up with food. Having meals at fixed times during the day can help regulate a cat's day and give them an internal schedule.
It might feel like 14 days is a lot and if your cat keeps this up every night you will certainly be tired by the time she changes her conduct. This could affect your mood and, if it does, will make it harder for you to maintain a "no-attention" habit at night. If you are able to keep it up though, and if this is not linked to something else that recently changed in your cat's life, you should be in the clear afterward and able to enjoy a good night's sleep.
Note that your cat might try to repeat this behaviour in the future, from time to time. If nothing else has changed, simply continue ignoring your cat and it will go away very quickly.
See this Jackson Galaxy video on the subject.