What Causes Severe Headache And Blurred Vision After A Head Injury?

I was in a severe cycling accident Saturday afternoon and was not wearing a helmet. I was going at a fast speed downhill to make it up the next hill. I hit some sand and instead of braking and wiping out, I went with the flow. It was only a split second thought. I landed on my back and the back of my head. My backpack obviously helped cushion me. Medics were willing to take me to the ER but I just had a severe headache. No bruise, no lump, no cut on my head. I still cannot walk well, vision is blurred and sometimes doubled. Research concluded concussion, so I have been taking Tylenol and have not been out of bed without assistance. It takes a while to think of words to put in sentences and while typing I have to correct lots of mistakes. At this time, should I still rest or get an MRI or CT scan? I was able to answer every question the day of the bicycle ride....even spelling words backwards. Most times the brain pain is unbearable...other times tolerable. Advice?