@Castro, the first thing you need to do/have done, is contact your bank to cancel the card so that they can issue a new one. I think any pending withdrawals should still go through okay as they will relate to your account number and not just the card itself.
With regards to your NEW card - if this is basically just a replacement card there should not be too much hassle fortunately.
If your bank issue you with a completely new card with different 'long number' then it can be a bit of a pain in the backside (happened to me recently when my bank cancelled the card due to unexpected 'activity' on it).
In this case you will need to wait up to 7 working days to receive your new card and pin number before you can contact all your bookie accounts to let them know and update your card details.
With some bookies you will be able to change the details manually in your account but a few might have to be contacted to do it for you. In all cases you WILL have to make a (small) deposit with your NEW card before you are able to withdraw anything to it (for money laundering reasons).
Could be worse - it could have happened days before Cheltenham, like me - eek!
If the old card is cancelled by your bank then I was told that any withdrawals to it should still be okay in the interim as it will relate to you and your account.
Good luck