Pink,
Your systolic blood pressure, (that is, the top number of 98) is low. Any systolic pressure below 100 is considered low.
Your bottom # is normal (80 or less). But as long as you feel well and have no symptoms of dizziness, fatigue, headache, fainting, or palpitations, I wouldn't worry about it at all! A lot of folks on this board would give their eye teeth to have #s like yours.
zuzu