advice please - when to test?

tested yesturday morning at what could be between 12-14 dpo and got a bfn. had only held urine for 2hrs. today could be 13-15 dpo still no sign of af which usually comes on dpo13. have been cramping on/off for days, creamy yellow cm, nausea and dry retching. symptoms only really showed up yesturday nothing until then. should i re-test tomorrow after holding for 4hrs or wait a bit longer?