I have back head pressure, constant dull nausea, and my anus is alway itchy? Sometimes there is blood from wiping constantly. Please help.

Will try. The two most common causes of anal itching are excessive caffeine and excessive moisture on the bottom. Cut out all caffeine, use plain cooking corn starch on bottom, do not rub the area, increase your fluids to 80-100 ounces per day and use a moist wipe to clean such as kleenex cottonelle. Do not use soap directlyon bottom, just plain warm water and keep the area dry with the cornstarch powder.
See a doctor. This could be a symptom of something serious like a tumor of the anal area. Most of the time, it is a benign condition. By seeing your physician, you can make sure that it is nothing serious - and at the same time get some treatment. This may be a chronic irritation that will respond to a cream - but you need it looked at!