Has anyone ever felt symptoms the day of conception??

So today is my ovulation day. Yesterday afternoon I had my peak LH test. My boyfriend d and I started bding the 18th and today I suddenly felt like this rush of exhaustion. And mind you, I got up this morning fully awake and I wasn't even tired. I had got a good night's rest last night. So I'm thinking my body may be trying to tell me that we may have conceived already. Especially since something similar happened with my first pregnancy.

Has anyone else felt anything like that?