CD 15 - am I overthinking this?

Not TTC but had a small "oops" CD 5 while I still had AF.  Wouldn't mind if it results in BFP. But here's how I'm feeling.
No obvious CM from ovulation (last 2 months it was very clear when I had it).
Up until today I was extremely unmotivated - ovulation symptom?
Today my stomach has felt weird. Not really nauseated, but on the verge of it as if I was slightly dehydrated, which is normal for me in the am, but it continued after drinking enough water. Maybe just need a lot of water today?
The past several days I've been more gas-y than usual.
Faint muscle twitch/spasm in lower back earlier but it stopped. 
Breasts feel normal, energy level is normal.
I think that's it and I'm sure all of it can be explained by other things, but if I am pregnant from sex on CD5 (we've had set since then but used protection), could I start having symptoms at CD15? I estimate I'm probably 2-3 days past ovulation, due for AF around 11/17, if I'm now back on track after stopping BCP in June.
Any feedback is great because I'm just driving myself batty by thinking about it. Can't imagine what I'll be like when we got of all protection completely!