OK, you've obviously had a long day OP and aren't feeling your best.
Let's add some rationale to the situation to break through the hormone fug though.
You only mentioned your previous health issues when people started getting a bit harsh with you. Those issues don't seem to be the reason you expected more of your boss. Pregnancy itself isn't really a reason to expect more either. And if your boss was used to having to hand hold more because of your other issues, he'd have done the same tonight.
It does sound like he was a bit abrupt though...up until that point, did you think you were getting in the cab together? The way you've told it, it sounds like he said it as he was getting in the cab, didn't give you a chance to respond then shut the door and drove off. If that's how it happened, it's poor form and I feel for you.
As others have said, you should have known where you were staying. And it seems you did, considering you then gave that location to 3 taxi drivers. Not taking responsibility for yourself is a mistake in your circumstances; one that I'm sure you're aware of now. But thinking of it properly...your boss being there wouldn't have changed the first 2 cab drivers not knowing where you were staying.
In the kindest way possible, if the fare was going to be small and you were upset and clearly pregnant, a less charitable cab driver may well claim they don't know where you're going. That seems more likely than 2 London taxi drivers in a row not knowing a local hotel.
Finally, I'm not sure how you think your boss is ignorant? Maybe not the word you meant?
Hopefully you've had a nice long bath and feel a bit less overwrought now. 