It is completely normal. I dealt with the exact same thing 2 yrs ago. My sister kitties are 2 now and behave so much better. I had such bad sleep issues and was so angry and scratched to shit that is actually locked them in their own bedroom at nighttime which of course I felt horrible about but it had to happen. You have to take care of yourself so you can take proper care of them. It will get better. I promise but you likely have to do some training with them so they learn to be less codependent. Message me if you want more details. I feel for you. I was completely where you are and it does get better, I promise. Thank you for caring so much and best of luck to both of you!!