No line this morning?

Kelly
I posted the first pic last night and I can definitely see the faint line. I took another one this morning (second pic) and now I'm not seeing anything. Is it possible that my hCG levels are higher later in the day?
I let myself feel the slightest bit excited and now I'm worried. I wish I could just be patient and not test for a few days but I'm obsessing now...
Last night:
This morning: