First off, I hate that it's called "Morning sickness." While I loathed the book, "The Girlfriend's Guide to Pregnancy" - so much so that I couldn't bring myself to even donate it because I didn't want others reading it (I recycled it) I did agree with the author on one point:
It ought to be called "Progesterone Poisoning."
That clears up the ridiculous myth that it's isolated to mornings (many women have it all day) and conveys the seriousness of the condition.
With #1, I really was fine. I had a little bit of queasiness. I vomited only once though -- was up much earlier in the morning than usual & rushing around a bit. Taking it easier & slower in the AM fixed it, like sitting down while I brushed my teeth.
I had a little fatigue, but nothing major. I was functional mostly all the time. It seemed to gang up on me on Sundays - ha! So I'd feel pretty good 6 days a week, then Sunday just spend all day on the couch. Convenient anyway since I had a lot of reading to do.

It didn't really disrupt my life at all - had my full-time office job, plus teaching aerobics, plus my own weightlifting & boxing workouts, chores, social events, etc. No prob!
But "poisoned" very accurately reflects how dreadful ill I've felt with #2 since 7W along. Exactly like a really, really bad wine hangover 24/7.
I'll be 12W tomorrow & just the past few days, nausea has lightened up, only to be replaced with headaches. So I'm still a mess & not able to function.

If you want to try to get something of an idea how you will personally feel, you might want to ask your own mom, if you can & any sisters if you have them & they've had kids. While it's certainly no guarantee, I do think there's some chance of some similarities. My mom has always said pregnancy & birth was such a piece of cake for her, "it was like falling off a log."

& she had 3 of us. My Gma said it was easy for her too - and she had two kids in her early/mid-30s.