Try not to give up hope in the moral meat grinder that has become college. Find a good prayer group and watch what you allow into your mind. A lot of the stuff you will run into will challenge your faith and may even try to break or infect it.
Thoughts are not all equal or harmless.
You can be (and it sounds like you are being) bombarded with secularism, materialism, relativism and humanism.
It is your choice to accept these but try to remember that a real relationship with your Creator is possible but it is a choice and you will be challenged both but the evil-one and current society. If you accept a lie into your mind and play with it as truth then you may end up forsaking your relationship with God by choice (even accidentally unfortunately).
The good news is that God is ever patient and waiting for you no matter what happens. It sounds like these thoughts are bearing (bad) fruit in your life and you do not like it. Try studying something more hopeful like Pope John Paul II’s writings.
God Bless