af should have been here yesterday

Maricica β€’ Mummy to Ella born sleeping 23/7/17 πŸ‘ΌπŸ»πŸ’ mummy to josh born 19/5/18 πŸ’™πŸŒˆmummy to maddie born 18/5/20 πŸ’–πŸŒˆ
Af should have be here yesterday but not yet am not sure what day I ovulation I could be 13 dpo today I done a test on Monday and it was bfn but on Sunday night and Monday I had back pain like I get before af but it away now when should I test again x