Late AF

This is my 4th day being late on my AF . And I want to test. But every other time I've been late and tested it comes the next day. I just don't wanna be disappointed by another negative test. Although this time I've had extremely sore nipples and a mild cramp in my left side on and off. And usually I don't get cramps til the day after I start AF. Maybe it finally happened?!?!