Is he flirting? guys girls please?

ok so there is a guy i really like i mean alot! he was dating my friend but they broke up. so hes in my cl and he talks to me alot and trys 2 make me laugh and 2 days ago he sat 2 aisles away and one seat behind me and was talking 2 me and constantly getting us in trouble and taking the blame for it.then he was makin me laugh abou his iimaginaryry friend and then when the bell rang i got up and was leaving but he was walkin beside me all the time and 2day he kept gettin closer to me like he would move desks closer to me nd sit as close as he could