Well, the thing is, brothel work is a bit of a beast. It's usually 10-20 clients a day at ?60 (or less) half hours - and you're only keeping ?40 because of the necessary commission paid to keep the brothel running. It is a much more secure environment, and they should provide a nice and clean flat, so in this circumstance I do feel that the commission is fair (unlike agencies where they often don't take security of the girls seriously, or provide an incall/driver/anything, etc). But it's still a bit wearing when every client still wants his 110% effort from you and there's just SO MANY of them.
I shouldn't really admit this (!) but I worked a grand total of 4 shifts in a fancy South Kensington establishment, about two years ago, and just couldn't hack it. It was 4 Fridays, so it's not like I didn't have recovery time, but I found that I was wanting to stop being touched by strangers after about four or six of them but unfortunately that's only 3 hours work and you've got to stay there for 10 hours else you'll just get replaced (I do understand that the owners have absolutely no need for girls who can only manage 4 clients maximum!). So yes, after seeing 15 in one day and feeling utterly broken (it's just upsetting to not be able to choose exactly who you're shagging and when you're shagging them, for me - I'm a born independent!), I couldn't go back. Not when I can earn the same amount seeing two or three clients in a week independently - and it's much more relaxing and fun for me being in charge of who I see.
Sorry, OP, I know that's not much help. I think we all know the advantages to brothel work - safe, not working from home, not having to advertise or answer the phone, etc - but there is a huge downside: the volume required/expected.
If you're happy to lose the earnings, you could try asking the manager/owner for shorter shifts? They may still expect you to pay a full commission amount, though, which would be tricky. Or you could perhaps share shifts (half each) with another girl who doesn't like being shagged more than eight times in a row?
You could even put together a bit of a routine for the standard bookings, which enables you to stay energetic, perky and fun throughout the day - so the clients still have a good time - but not spend any energy having to think too much about what to do. You'll probably already have a routine, though, so maybe just develop it so that every 30-minute job goes like x-y-z-done-yay! and the time flies and you can of course chat to clients and tailor their experience for them, but mostly they do just want a rather standard thing (to be honest, it's really hard to do much else in such a brief time!) and having an almost automatic thing can help you conserve energy throughout the day. Not being robotic, of course - still plenty of room for chatting and sharing jokes and doing the GFE thing - but just making sure 90% of short bookings run really smoothly.
Also, I'm not completely sure whether you wanted tips regarding... the psychological aspect? (If so, it may be that being able to take charge of your working hours a little could help; feeling like you "have" to see dozens of clients in a day is horrid, while
choosing to see 'only' ten a day could actually feel much better, because it's
your decision.) Or is it being physically knackered? (It's hard to eat during a workday in a brothel, for the obvious reasons of stress and perpetual condom-taste, but you must try to get some good quality nutrition for energy if you can. It may sound shocking and sacrilegious, but a whole milk latte gives much more energy and satiety than silly 'skinny' drinks, if anyone's going to the coffee shop for you! And if you can keep some honey in the kitchen, stirring that in will give you some simple-and-good sugary energy on top. Foodwise, anything you can nom in two seconds between showers and blowjobs is essential - high protein stuff will provide more lasting fullness and energy, here.)
Or if it's neither of those things that's bothering you, just let us know what is and we can try to help.