You aren’t sinning I’m sure.. I know of a woman who had the same procedure as you… she also felt the same and asked her priest who told her its not a sin because of her health issues. You are being responsible and also because of your c-sections another baby may be an issue. Sweety you are NOT sinning. I could drag out a heap of scriptures and etc but I’m sure you aren’t. I have a priest I’m close to who I can ask if you like and post back.