Why does my 11weeks puppy always cry at night?

I gave her her toy tonight to play with to see if she would stop crying but its not working and its breaking my heart! She slept for all of 10mins and thats it. She sleeps in my room with me and when she cries soo much, I cant sleep and bring her downstairs so I can have a smoke. I dont want to leave her downstairs on her own as she will cry either way and I would just feel cruel! Can someone help me?