Pregnancy tests

Kelly
I've heard the best time to take is a pregnancy test is in the morning: your first pee of the day. Is that true, or it doesn't matter? 
  I got into a really bad accident on Memorial Day weekend and haven't had a period since. This week I have been so damn moody and crampy.. Back aches and breakouts too. It could be my period getting ready to start, as this is how I often feel before I start my period. But I've been feeling like this since Friday last week. I took a test today after work but it was BFN. Should I test again tomorrow morning?