It depends J..
I had horrible morning sickness with both of my kids. I didn't throw up during the day, though. I just has such horrible nausea that I could barely function. Every morning, my day started with me in the bathroom throwing up stomach acid for about 20 minutes. Then, I didn't throw up the rest of the day, but neither did I feel up to doing anything. Some days (many days) no shower, even.
With my son, I was able to muddle through and work up until about 3 weeks before my due date. But I had a laid back desk job and my boss was very understanding (and rarely in the office). I was able to nibble food almost constantly, and it helped keep the nasty taste out of my mouth. Sea bands, ginger (snaps, ale, tea, etc), and crackers did nothing for my nausea.
With my daughter, I was NOT functional, even though I was no longer working outside the home. I essentially laid on the sofa and hoped my son didn't burn the house down in the early days (after my husband couldn't burn anymore sick leave, and before we packed up our son and sent him to grandma's (in-laws). I also spent time at MY parents with our son, so they could help with him (he was 2). I rarely made meals. Laundry was iffy. House cleaning didn't happen.
My doctor put me on Zofran and it HELPED. I was able to function and husband didn't have to stay home and we didn't have to ship son off anywhere else, but I still was able to DO very little. I spent a lot of time on the sofa with Disney movies on for our son. :(
It is a difficult thing to know, how much your co-op mom is suffering. Some people ARE drama queens. Some people tough things out through things you or I could not, no matter how seemingly impossible. Most people are somewhere in the middle.
For what it's worth, my nausea lasted until the day my kids were delivered. It did not go away at any point during pregnancy. We have 2 kids, and we decided no more after the 2nd one, mostly because of how incapacitated I was during both of them. I was completely miserable for almost 10 months each time. I have said before many times: Labor was a piece of cake and I could do that all day long.... just do NOT ask me to be pregnant ever again.
ETA: Just wanted to throw in also that the ONLY time in my life I ever felt depressed, was during pregnancy. As another mom mentioned in her post (somewhere below mine) what should have been some of the happiest days of my life, were the days that made me feel depressed. I woke every day with a sad "Oh God, please help me get through this day" plea, and an understanding of what people who have no hope feel. I knew with pregnancy #2, that I was going to be that way for 9 months. That is a long time to know that all you are going to want to do for 9 months is to crawl in a dark room and hide, pray for sleep, and for time to pass. Especially when you can't do that, you HAVE to be awake and alert to care for others.
The dentist I went to after my kids asked me if I had ever had an eating disorder (it damages the enamel on your teeth). Ummm no. I just had dry heaves with stomach acid for 9 months twice.