I have a pair of climbing shoes that I bought from 5.10 (Five Ten) Dragons and it is 1/2 size smaller than my regular pair of street shoes. I started having blisters after a day wearing them to try and break them in. Also, I cannot put pressure on my big toe because it hurts. Is the size too tight for a climbing shoe?
It does not sound like what you are are too small since most climbing shoes tend to stretch out. There is more pain involved in breaking in a climbing shoe that is designed to be aggressive. Do not think too much about the blisters because it may hurt for a while but they will heal and toughen up.
To break in your shoes, try wearing thin socks and walk around your house. If you cannot physically get your shoes on with the thin socks, then, try putting your shoes on and stand on the balls of your feet and alternate the heel that you are lifting off the ground. Stretch out your shoes as much as you can. And lastly, go climbing and put pressure to your toes as you slowly ascend.