Answer: gloomy mood
In this excerpt, Montague describes how his son Romeo appears to be depressed. He states that Romeo has been crying through the night, constantly sighing. He also seems to be averse to light, and as soon as light comes through his window, he draws the curtain. Moreover, he stays in his room all the time. This attitude, and in particular his reaction to light, show that Romeo is in a gloomy mood.