Could this be a positive - faint line

Sarah
Please please help me ladies - we've been trying to conceive a while now - thought my chances were out this month as I was sick. I have a 28day regular cycle and was due AF today... So far she hasn't showed! I have had some ovary cramping this morning and have the worst lower back ache!! 
I've done x2 tests ... Is that really a faint line I see on the top one?? Could it be? I read the test within 3 minutes... That one has a higher HGC reading needed of 25mlU and above, but the lower test is meant to pic up 10mlU... But that's showing nothing really - maybe a slight shadow if I catch the light right!! Please help ladies .... Can I get excited???