feeling nauseous, what could that mean?

That you should take it a bit easier.

That you might have a bladder infection or that your baby is already a bit lower. If you're not used to this, I'd still recommend contacting your midwife. It's somewhat normal at this stage. Also call if these contractions come regularly. In short, just give them a call. Better to call too often than not at all. They're there for you even on weekends.

Says nothing, really. I had it with my first pregnancy too. Very annoying. But the OB-GYN said it's totally normal; with your period, you get those feelings because you're losing blood, and now you get them because a baby needs to come out. However, this doesn't mean you'll give birth soon. I felt it between 28 and 30 weeks, and ultimately gave birth at 39+1 weeks.

I'm now over 36 weeks and have been feeling it at certain times of the day for a few days.
Is it your first baby? I suspect it has to do with the baby dropping down.

I've had that for a few days too.
Or hard contractions combined with sharp pains low in my uterus.
Had a check-up with the gynecologist yesterday, and I need to take it easier.
It's a sign that you're asking too much of your body.
Now I'm usually lying at home in the armchair, because walking to the toilet results in a painful hard belly.

I don't think it's your labor starting, but rather your body telling you to take it easy for a while.