Clearblue Bfp then bfn the next am

I had a gut feeling yesterday that I should take a test. Around 3:30 pm I took a clearblue digital. It read pregnant! Then I retested this morning and got two 'not pregnants'. What are the actual chances I got a false positive? AF isn't due for 4 more days. Should I call my dr. Or wait to test later in the week? Really hoping the first test was right!