Help Me!!

[MamaK]

Seven is 9 months old. We have co-slept with her since the day she was born and it has worked for us.
My situation is this: Seven WILL NOT sleep during the day. She wakes 3-4 times per night for a feed, which never used to bother me, but now I am so exhausted I am finding myself getting angry about the situation.
Seven can be awake from 8.30am to 8.30pm. She sleeps well at night, but wakes frequently.
We have a night time routine, and getting her to sleep at night is not normally a big issue, it only takes about 10-15mins.
We have tried Seven in her cot - no go.
I 'wear' her to sleep but the most she will sleep during the day is 40 mins. She has NEVER slept longer than this.
I find that I am getting angrier and angrier at this little person who is taking so much out of me.
I don't want to give up BF but I just don't know what to do!
I have lost a lot of weight, whether it is because of BF, lack of sleep or just me or all of the above, I just don't have the energy to do this much longer.

All she does all day is cry. She doesn't whinge, she screams. And it doesn't stop.

I love my daughter, I am just so tired.

I need help....