Im worried i may have taken too much fragmin. are the signs and symptoms immediate? what should i look out for. i have a major headache, but i also didnt get much sleep and havent eaten yet?

I'd be surprised if you developed spontaneous intracranial bleeding from an inadvertent high dose of fragmin as I expect you have a healthy & intact network of intracranial blood vessels. Nevertheless, if this headache is much more intense or persistent than your usual headaches or if you're experiencing other symptoms, I advise being evaluated in the hospital ER where prompt testing is available