Please do not stress about this. Assuming that you booked directly with ba then a quick call when office opens will resolve.

You will be required to fax a copy of your marriage certificate and pay gbp30.00 and the e ticket can be reissued for you. Do not delay, however, as the taxes etc will be re assessed to check for any increases and although this will not be a problem if you deal with it now, as time goes on there is always the chance that these could go up.