I don't want to scare you. I am on this forum because we are trying to conceive. But when I saw your question I thought I would share. My mother is a breast cancer survivor. A leaking, tender breast was her first symptom of the disease. (keep in mind - she is a survivor)!!!!
Although you may be pregnant the chances of a failed vasectomy are slim. Even if a few living sperm get through (which is rare) the chances it will make it to concieve are even slimmer. Although I have heard of this happening. I hope for the best for you! Take a preg test!