I think I'll go upstairs and have a sleep.

我想上楼去睡一觉。

You may have a sleep disorder.

你可能患了睡眠障碍症。

I'll go upstairs and have a sleep.

我要上楼睡一会儿。

I like to have a sleep after lunch.

午饭后我喜欢小睡一会儿。

I like to have a sleep after lunch.

午饭后我喜欢睡一会儿。