The answer to your question is yes, you are still a Catholic given these circumstances. You have chosen to injure your communion with the Church through impenitence for what you know to be mortal sin, but that does not mean that you are not Catholic.
Perhaps you should be asking yourself some other questions: Why do you care if you're Catholic? Despite protests to the contrary, are you starting to feel uncomfortable with choosing to do something you know full well the Church doesn't allow? Have you ever given careful consideration to why the Church teaches that in vitro
fertilization is a sin? Have you given thought to the idea that just because man can do something does not mean that God approves of it?
The Church has very serious reasons why it objects to in vitro
fertilization, and many of those reasons concern the rights of children and not the desires of parents. The Church believes that children are a gift from God, so much so that they can never be considered something
to which any other person has a right. The Church recognizes that married couples suffer greatly when infertility ends their dream of biological parenthood, but urges them to offer up their suffering and to find other moral, just ways to become parents or to live out spiritual mother- and fatherhood. Those who choose to ignore the Church and engage in such immoral means of procuring children can be restored to communion with the Church -- and the Church never condemns the innocent children born of such methods -- but they must be willing to acknowledge first that they were wrong.
Why are artificial methods of conception immoral?