well for me it started at 4 weeks and it was always bad in the evenings but not bad in the mornings at all. i remember i woke up soooooo hungry that i felt like i was going to throw up if i didnt eat. i still feel that way too but its definitely more of a hunger pain than a morning sickness one, because morning sickness made me constantly nauseated. at week 10 not even food helped because my morning sickness got to the point of vengeance because it was on and off throughout the first tri. it was normally mild anyway, you know, basically just going away or becoming mild whenever i ate food. but one time i didnt feel sick at all even when i didnt eat and then i got worried but the next following two weeks was HORRIFIC... like morning sickness was the worst it could ever be. it went away for good in week 12. MS varies in intensity for everyone though so sometimes it could be so bad that smells trigger it (not for me though) and other times it could be mild that it goes away after adding food. some women cant even keep down liquids for a second. for me, i think the iron in my prenatals made it all the worse.