My twins are now 2 but just read what you said about the difference between twin and singelton pregs....
Twins ones are more than twice as hard !!
I had a singleton first and that preg only got very hard in the last few weeks.
It makes sense really, at half way through my twin preg I was the same size and carrying the same weight as a singleton mum at full term. BUT..
... the big difference is, in my opinion, if you are near the end of a single preg you can rest, kind of give up everything, ask for loads of help from everyone, as you only have 2 or 3 weeks left.
But with a twin preg when you get to that same size, you CAN'T collaspe, call in all help because they is still 4 1/2 months- ish left ( if they are not early ).
Most twin mums at half way have not gone on mat leave yet and its just too long to rest all the time and stay in.
When you are near full time as singleton, you naturally get sensisble, call in all favours and hibernate / do as little as possible. That is what twins mums should be able to do also, I think.
It was a full time job for me, just eating rennies, swigging gavison, trying to find food I could eat, and trying to get some sleep... from 4 months onwards.
Mind you, I went full term with my two and they were 6 and 8 pounds ! It is SO worth it once they are here. I found first month with two newborns was easier than the pregnancy, if that helps ??