Please HELP!

My exN is at work and it is completely terrible I was doing NC for a week and doing so well but then he emailed me yesterday to ask if I was still mad and stupidly I replied with a smiley face. WHY would I do something so stupid I feel like I just let him abuse me all over again. Now this morning at work I saw him walking with his new supply. I am currently having a true emotional breakdown I cannot stop crying please someone help I have no one else to talk to. I