If there is a faint line, it stills means your possibly pregnant.
Hpt's pick up the hcg hormones that you put out when you preggy. My advice is to take another one tomorrow and see if the line has gotten any darker, and if it has go to da doc.
I took a hpt the day my period didnt arrive and it was faint. Then I took a clearblue easy digital hpt. Then it spelt out .P.R.E.G.N.A.N.T. And well noe im waiting on my first visit. Im 4 weeks and 4 days.
Hope this helps!