Can swallowing your own blood make you sick?

Yep. It can upset your stomach especially if you haven't eaten lately, because there is iron in your blood.

Just have a good drink of ginger ale and something like a baked potato or some oatmeal or bread - something benign that will dilute it, so there is more other stuff there than blood. It won't take much to fix it. DOn't have anything acidic until morning- no coffee, tomato sauce, fruit juice, salsa (eek!), ketchup, onions, nothing spicy or greasy. Pasta and a little butter would be fine - but drink something non-acidic, and then have something to eat.