OPKs detect LH, which signals your body to ovulate when it surges. There is LH present throughout your cycle, so you're likely to see at least a faint line for potentially your entire cycle. The only time the OPK reading matters is when the test line is as dark as or darker than the control line; that's your positive, anything else is negative. So it means nothing that you're still getting a faint test line, especially since you're charting BBT and I'm assuming that you know you have actually ovulated since you mentioned a temp shift.
If you keep testing with OPKs and you get another positive shortly before or when your period is due, and your BBT is still up, it could be an indication of pregnancy, though you should still confirm with an HPT. However, at this point, faint test line on an OPK and BBT going up is well within the range of normal, whether conception occurred or not. Give it time.
at 4:01 PM on Feb. 16, 2011