Is anyone else terrified of pregnancy?

I'm 22, and recently married. My husband and I have discussed at length our desire NOT to have children. We are both still young and both are finishing college and want to travel. We don't want the responsibility of children, and don't see ourselves ever willingly taking up the parenting role. Because of this, we are extremely careful about birth control. I am on the pill continuously and do not take my placebos. He always uses a condom and when we are feeling particularly paranoid he also pulls out. Even with all of these precautions, each month as it nears my period I am always terrified that I might be pregnant. Things like implantation bleeding and cramping absolutely terrify me because they "mimic your period." Any twinge or cramp I panic. If I feel tired, or get a headache, have a stomach ache, or get lightheaded, etc. I panic and become extremely anxious that I might be pregnant. I know we have a very very very low chance of becoming pregnant because of the precautions we take, but I DON'T want to be pregnant so badly that I am overcome with fear and anxiousness at any sign that our precautions may have failed. Can anyone else relate to this?