Have you experienced recent significant weight loss even though you say you are overweight ?
Any change in your bowel habits recently, like alternating constipation
and diarrhea often ?
Usually bright red blood in stool
can be due to variety of factors like hemorrhoids, anal fissure
which will be associated with pain on defecation, inflammatory bowel disease
, possible cancer of colon considering age factor, bleeding disturbances etc.
It is advisable to have a diet rich in fresh fruits and green leafy vegetables. Stay away from red meat, excess carbohydrate
food, fatty food, junk food, colas etc. Drink enough water. Sleep 6-8 hours a day. Do daily brisk walking exercise for 40 minutes a day. This will help to maintain good health, proper weight, better energy levels.
Since you have light-headedness, it is possible you may be anemic or low blood in your body due to the bleeding.. It is wise to consult your Doctor and get a thorough checkup and also blood work done to find out if you are anemic. Also keep your thyroid levels in check.
Kindly report further for follow up.
I hope I have answered your query.