You sincerely asked God and He gave you your sign, wonderful! He gets that your mind bounces back to negatives thoughts, just keep thanking Him and saying you are sorry for the negative thoughts. Truth is, it was probably the enemy making you doubt, the thoughts that run thru your head aren't all yours. Just watch stuff like that go by and don't entertain it. The enemy often comes by to try and steal what God blesses you with. Just recognize him for the leech that he is and laugh at his feeble attempts to steal your blessings.