If it is any kind of anemia, like Sarah is talking about, the interventions she mentions will take a long time to work. You can take vitamins and eat right and exercise and it can take a long time (months) to make more blood and build up iron stores. It is a good idea to get a blood test to see if you are anemic and what type of anemia you have. Then, it won't just take vitamins and diet, you will need to try to figure out how you got that way.
Like Sarah said, it could be other things, too.
Total abdominal hysterectomy at age 26 due to abnormal bleeding. Kept ovaries.