Worried I got a false positive

I took a clear blue test first thing this morning and accidentally forgot about it while getting ready for work. Noticed it less than an hour later and it had what I would think is a blue positive test result, but I’m worried it was an evaporation line. So when I got to work I took another test and it was negative. If I am pregnant I would be around 5 weeks. Could the negative test result be because I’m not far along and did not test first thing in the morning?