Does Having Protected Sex During Ovulation Cause Pregnancy?

I had sex with my boyfriend on Monday (Jan 18), so I guess 4 days ago. I'm not on BC, but we used a condom, and he pulled out before he came. We're almost positive that the condom didn't break either. We were as safe as we possibly could be, so I feel as if I couldn't be pregnant, but I'm so nervous.
My last period was Jan 1-6, so according to my app my fertile week was the 10-16. But since I'm rather new at trying to keep track of everything I don't know the exact length of my cycle. It tells me my period should come in 8 days, but I'm so nervous that it won't.
I feel like I've had really early symptoms, my breasts are starting to hurt when I put some pressure on them (like pressing), I have slight backaches (kind of like needing to be stretched or cracked), and occasionally I'll notice that I have a cramping feel (like it could be a period but it's not).
The discharge I have right now is sticky, and I haven't spotted yet, if I will at all.
Could the pains be from being so nervous, my period coming in a week (hopefully), or because I could possibly be pregnant? I plan to test but the anxiety and stress of not knowing is really affecting me.