My doctor told me I was slightly anemic. What does that mean ?

Just what he (or she) said. Were suggestions made to you on how to improve your blood levels? Although you may not be in danger of any serious health issues as a result you may feel "run down" and would function better if your counts were solidly in the normal range. Most cases of anemia are easily addressed and remedied. Follow your doctor's instructions and ask to be rechecked in a few months time.