TMI sex question

I'm 33 so I'm not new around the block but never tried his before. Last night things got hot and heated fast with me and the husband. The kids kept waking up so to hurry up and get things done and more discreet if a child walked in the room he went right under the covers and performed oral sex on me. Usually we have sex after but he laid back like, my turn. So I returned the favor. Here's the question......when he was almost done I was like oh shit this is like most fertile day to have sex what am I doing?!?! So when he finished I spit it in a cup, laid back, legs up and used a syringe to insert his sperm into me, was that useful at all? Or did I make myself look stupid doing it?? I've heard all the stuff when I was younger of be careful even pre cum near your vagina can get you pregnant so I figured at least that'd get some of his swimmers up there for the nite. Help me out please I'm sooooo overthinking and worried cause I feel like I lost the best day of this cycle and want to have given myself at least a small opportunity that day to ttc!!! Thanks in advance for any advice or tips or answers!!!