Each pregnancy, I swear I start feeling sick the moment that sperm hits the egg.
My first pregnancy, I first woke up feeling sick about 5 DPO. Second pregnancy, I wasn't charting, but it was in that same range. This time around, I started feeling sick in late June, about a week after ovulation and a week and a half before I got my BFP.
Mine is usually worst first thing in the morning, but I can usually make it better by eating crackers. I seem to vaguely remember Wave #2 coming in the afternoons with my first, but soon learned to keep my blood sugar up by drinking my daily OJ with 7-up mixture about 2 hours after lunch.
(Like many things I am driven to consume while pregnant, I have no idea why I so strongly felt I needed a glass of OJ with 7-up every day. Actually, my first instinct was a Cream and Kahlua, but since that was out, I settled for the OJ stuff.)