Is the veneer actually broken or did it just fall of your "base" tooth? I have a couple of veneers and once or twice...seems like whenever I chew rib bones
....one has pulled off the tooth it was attached to < damn dangling participle!
I found that the tooth repair stuff you can buy at stores like Rite Aid, Thrift Drug, etc. holds pretty good. They sell a little tooth repair kit for a few bucks which has an adhesive putty, you thoroughly clean the veneer and put some putty on it and reattach it. Mine held for several days before I could get to the dentist for a more permanant fix.