Blood when wiping after bowel movement, stomach pressure/cramps after eating and increased gas. no external hemorrhoids. what could cause this?

Blood in stool: Go to see your physician. The current symptoms could possibly indicate that you may have inflammation or infection of your colon-i.e. Colitis.

GI disease: Gi symptoms are complex and difficult to determine on a site like this. Irritable bowel, crohn's, hemorrhoids, food intolerance, etc are all issues that need to be explored. A visit to a gastroenterologist or even a cool-rectal surgeon appears to be in order to define the problem and treat the underlying cause(s).