You asked for suggestions:
take her to park as much as possible in morning making her run backwards and forwards until exhausted. then fill with custard or somesuch at lunchtime. then put on very dull DVD... will work wonders...
send to nursery or childminderif you can afford it if not already for half or one or more days. No really. Don't feel guilty and don't listen to Dh if he protests. You need to energy to cope with two and getting a bit of space to sleep while in last trimester will help enormously
remove all furniture she can climb on from bedroom, screw all remaining furniture to wall, remove any dangerous stuff, then fit baby gate to her bedroom. If she gets out of bed, tell her she stays put quietly for an hour regardless. If you can't bear to just leave (and you never know she might like just to sit and look at a book, mine did) then offer bribes with a sticker chart for staying in bed...
drive on motorway for half hour to send her to sleep. Park up in service station. Put seat back and ZZZZZZZZZZZZZZZZZZZZZ. drive home
take her to bed with you in afternoon.
swap playdates with friend - gives you a couple of hours free and also having someone else over might distract her for a bit from terrorising you
go to cinema. she'll be transfixed/terrified into silence, you will fall asleep with boredom instantly and only wake up when credits rolling and she wants a wee...