confused about him

i m doing mtech n he is in my class....we both used to talk few days before......everything was nice....suddenly he stopped talking to me started avoiding me....so i used to ask him why he is doing so......first he replied calmly that nothing serious n all...but all of a sudden he stopped talking to me blocked my contact...asked me to stop irritating him n all... But still he stares at me in class.. i do not know why.....his eyes tell me something whenever he looks at me ....n he always notices me in class..but still does not dare to talk with me on phone...m confused that what exactly he wanna say...he really ended up with me..or still have feelings for me...he want to talk with me or not........what should i do upon his behaviour????