Im a 18 year old female and my blood pressure is 86?

Bp: If you feel well with BP of 86 likely not a problem. If you want to try and increase it increase your fluid and salt intake and see if BP goes up and changes how you feel.

Need more info: Blood pressure involves two numbers. The top number is the systolic pressure or the pressure when your heart pumps. The bottom number is the pressure in between beats. If your systolic is 86 then this would be a low blood pressure and you are probably experiencing dizziness or other symptoms upon arising. If 86 is your diastolic then this number is normal. Need a complete BP to really answer.