How soon do you feel any "symptoms"

Val
I know it's virtually impossible to feel ANYTHING after conceiving, I think I'm still in my fertile window(last day) but on Friday after BDing the first thing my fiancé said was "I just got u pregnant, I felt it". Now were not actively TTC, if it happened great. Well we weren't actively TTC, but now I think my fiancé wants it just as much as I do. If anything this would be our 2nd month.  I was a little sad last month when AF came but I have the mindset of when it's suppose to it will. 
​I don't know if it's bc he made that comment or what but I just feel very off. I'm tired, nauseous, and boobs are somewhat sore. Now my boobs being sore could be from ovulation. And truthfully I think it's very impossible to feel ANYTHING bc implantation most likely didn't even happen yet. 
​Last month, I coulda sworn I was preggo every symptom I felt BUT it's also very similar to PMS. A lot of my friends tell me you "just know" well I'm not going by that lol.
​What's the earliest you get symptoms and how can you differentiate between PMS and pregnancy? Also, how accurate is flow? Bc technically last month, it was my "ovulation" day and nothing. I understand it doesn't happen right away, but it also makes me nervous that maybe I can't get pregnant