Unhappy [Q] Xperia SP boot/flash major problem

Hi all

Please can someone help me. I successfully unlocked bootloader, rooted and updated my Xperia SP to DoomLord's leaked 4.3 ROM, however, something has gone very very wrong. It was working absolutely fine until today when I restarted my phone and it comes up with the Sony logo, Xperia logo and whilst it is booting with the colour stripes, it freezes and reboots. It keeps doing this loop. I can no longer enter CWM nor can I enter fastboot mode. It can go into flashboot mode but not for long enough to do anything with.

Please please please can somebody advise me.

Andy