I think it can be entirely different for each person. Making it hard to know when something is really a Pregnancy symptom or not.
For me, as much of a cliché as it sounds, I just *knew* I was pregnant. I felt so different that even before I took my test, I told my hubby that I knew 100% it was a positive.
I started off feeling tingly and sore in boobs, a breakout of acne on my face and neck, a really unusual smell down there (Sorry, tmi!) and just this weird feeling that my body felt different.
Wishing you the best of luck on getting your BFP!