Sorry to hear the loss but been their many times myself, everyone has given excellent advice here, like many have said its a not a sprint but a marathon, have to try and look at the long term here.
I had to make many adjustments, lowering my stake or ignoring fights and simply waiting for a better card or better fight, doing my best to not chase (although very hard to do), you need that right mind set of being the turtle, you may take hours to get to the finish line but you will get there and win, while ignoring the rabbit.
I say to ignore the rabbit since its easy as blokes to see other people hitting crazy winning numbers around here and lets face it we all want a piece of that, but one has to be happy for them instead, its not a competition remember your end game is to be successful long term.
Keeping a separate bank account and managing bank roll is key, something mentioned above so almost think of it as money you are almost willing to lose, try not to dip into your savings or wages, don't quit that day or part time job either its an guaranteed steady income to pay bills. Separating these will help you keep more disciplined in your approach. I also regularly withdraw money every month usually one or two units, so if I lose a big amount its almost been covered through regular withdrawals and I don't dip into that so my savings or regular bank acc remains in the +.
UK bookies have a motto, loath it but its true 'when the fun stops,
stop' easier said then done and I bet most of us ignore it with the chase.
http://www.whenthefunstops.co.uk/
Again not suggesting to stop, and hey you made 40K in your b365 account? So somewhere you had great success, did you argue and get your money back from them? there have been reports of bookies blocking large withdrawals before, you can post here for further advice.
http://www.sportsbookreview.com/forum/sportsbooks-industry/
try this also:
http://www.sportsbookreview.com/sportsbook-complaint/