Poor amybelle, sorry you are having such a tough time. Don't feel bad if you want to stop now - it won't be doing you or baby any good to plough on if you are not feeling up to it. It used to be mandatory to start ML at 29 weeks, that only changed shortly before I was born.
Have a think about the best balance in terms of starting ML early, taking sick leave, and using annual leave. Do you have a sickness allowance? (i.e. where you get paid full pay not statutory sick pay)
I ended up finishing work at 29 weeks when I got admitted to hospital. HR tried to persuade me to take me ML early, but I decided I would rather use up my sickness allowance and then take statutory sick pay up until 36 weeks, when my ML would have been trigged anyway due to being off sick for a pregnancy reason. In the end, it didn't actually matter, because DS decided to arrive the day after I'd decided that!
I didn't like the idea of using up annual leave when I was sick, but if that will make life more comfortable for you, do consider it. I've hear other women use annual leave to cut down the number of days a week they do.
I thought (maybe someone will correct me if I'm wrong?), if you do a physically demanding job that cannot be altered to be suitable, work has to pay you even if you can't do your job? Maybe someone more HR knowledgable can advise on that one.
And try not to worry about how it looks to the team - they should understand what hard work it is! My team were practically begging me to take it easy in hindsight they were probably right