I've been there. I hope you have a good night's sleep and get to the bathroom in time in the morning. I ended up putting towels down on the floor as well at my worst, because getting out of bed after a couple of hours sleep was hideous, if I'd have been able to sleep sat on the loo I would have done.
There is a facebook group you might find helpful, called menhorragia support group. Lara Briden's books, website and podcast may also be helpful for you.
A lot of people swear by ginger root tablets or ginger of any kind to help reduce their flow.
I don't know what type of bed pad you have, but I have both a mattress protector that is waterproof on the back, and a "smaller" (still pretty big!) blue pad for incontinence that tucks in both sides of the bed and keeps it secure even though I'm a proper wriggle bum. The top pad is both absorbant and waterproof backed, so any leaks have landed on that, and not even made it as far as the sheet, which is a relief and much easier to deal with.
Look for incontinence products, rather than period products - they are designed to hold SO much more. Lots of us swear by the Always full incontinence briefs. I've had some success with some fairly cheap post-partum pads from Amazon, although nothing deals with the clots, they all just sit on top. If you are in the UK you can talk to Minivivi who make reusable sanpro and incontinence pads and she has some fabrics and products that help with the gushes, if you get those.
Finally, I had huge success with a medical herbalist's prescriptions, and their recommendations to eat more phytoestrogens.
Very best of luck to you. It's atrotious, and GPs are shit about it.