Fertile CM Length?

This month I am not using opk’s, I’m tired of them. I’ve noticed fertile cm for 7 days now, so when exactly is my fertile window? I have no idea my day of ovulation, because a chemical threw my cycle off awhile back. So when do I count the start of my fertile window if I’ve had fertile cm for a week already? I’m hoping I’m still in the fertile window right now because my husband will be here from working out of town. He comes home every weekend, last weekend was the start of my fertile window so I thought according to cm and app. But here I am a week later still with fertile cm. He only gets to be here for two days each weekend so I’m really hoping those two days are enough to get pregnant. Do y’all think 2 days at the beginning of fertile window is enough? Hoping someone can give me some knowledge about this stuff. I usually dry up immediately after the 5 days of fertile cm, so this month is weird. Help a lady out? Thanks ladies.