being exhausted, falling asleep during several of the prayers, catching up on sleep at every possible moment, but still able to fulfill your duties.. when is it "taking up your cross" or "maybe this order is not for you"?

there's also "suck it up! you'll get used to it.." what if you don't? when is it just too taxing and you fear it may affect your health?

at the moment it is probably the main reason why a certain order doesn't seem right to me, although it has many of the other qualities i do like.

so far i've been told that you just need to work it out with the prior or novice master, and if worst comes to worst, then you'll both decide that it just isn't working out.

There's a certain amount of give and take when you move into community. You have to get used to everyone and their schedules and they have to get used to yours. The community will never be the same when a new member enters.

That is why a decision is made over time. You really need to spend time with the order you are considering, and that means living the life for an extended period. Most have live in periods required. There is no disgrace admitting that a certain lifestyle may be too difficult. Again, that is why there are so many orders out there, and ways of living the religious life. That may be a sign that this is not the place for you, so keep looking.
There is always a time of adjustment, and learning, but if you know that the particular lifestyle is just too physically demanding for you, look elsewhere.

Perhaps the community has practices that are too difficult, or perhaps your body and mind must adjust to the changes of the schedule. Being able to adjust might also depend on how much penance and sacrifice are already a part of your lifestyle.

If you are called to a community with a difficult schedule, God will give you the grace.
For example, I'm a sleeper. I need lots of sleep. But I am sure that God is calling me to a community that's charism is one of perpetual adoration... so I will be rising in the middle of the night some nights to adore our Lord for an hour. I have told my concerns to the vocation director and she said that God's grace will be enough. Even if it takes me a long time to get used to it, God's grace will get me through.
So if you feel like God is calling you to a particular community, but you don't "think you can do it"... Give that concern to God and He will take care of it. You will be amazed with what His grace can do!