5w 2d no sac on TV u/s

Anyone been in the same position? Went in today for one sided cramping but no bleeding, or spotting. Everything looked normal / no enlarged ovaries, tubes, good thickening of endometrial lining, but nothing visible. Did hcg test today and will do again in two days, she didn't seem overly concerned said it was way to early to see anything and that if symptoms worsen to call her again. Next apt isn't until about 8w 3d weeks along which is July 24th. Should I be scared or nervous?