how did a bug get in my house?!!!

Not just any bug, but a bonafide cockroach! EWWWW!!! I actually cried upon discovering him. That is how scared of this damn bug I am. He was sitting in my bathroom sink. And I got home from work, all alone and husband-less and took off my jewelry and place it in the cup next to the sink and turned to wash my face and jumped ten feet off the ground and screamed and an away. i grabbed the phone and my husband talked to me and calmed me down and convinced me to get the bug spray. I must have sprayed that thing for a good three minutes. He twitched a lot, which made me scream louder and cry harder. Then he stopped moving and I kept spraying. and now my bathroom counter is covered in bug spray, but he is definitely dead. (I hope!) hubby will be home in 4 hours to ensure it. But until then, I cannot take my contacts out cuz I am too scared to go into the bathroom. How sad is that?!