I'm almost 17 years old & I'm a girl. This will be the fourth week I have been lightheaded. it's been everyday but some days are better than others. Everyone says I should go get blood work done, but I don't want to until I think its serious. A family member just got mono, so I think it could be that. I feel very off balance and there's a small shortness of breathe when it gets really bad. I do have asthma that acts up when the wheather changes but its never lasted this long. My inhaler does not help.