How come it seems like he likes me... then ignores me???

So me and my ex broke up about 8 months ago, and it was really terrible, so we still don’t talk to each other (I want to talk to him, but every says I should let him come to me) but I still like him and I’m having trouble figuring out if he feels the same way. If I ever catch him looking at me hell look down, but sometimes we just keep staring at each other, and I always walk by this bench when I go to one class, and hell always be sitting there, sometimes hell look at me and sometimes hell pretend he dosen’t see me if I’m staring at him. And one day when all my friends were sitting with him I came over and sat with them and he laughed at everything I said but still didn;t talk to me and when I said something and then looked at him he smiled a long time but kept his head down. But what is confusing is some days he’ll avoid all possible eye contact with me, when some days he cant stop staring, and, instead of laughing at my jokes hell walk as far away from me as possible, like today when I was walking with our friend he wouldn’t look at me and kept dragging behind, but as soon as I was far away he started talking to him again.I am really confused, and kinda mad that sometimes I am hysterical, but other times he cant even be himself around me. what is your opinion?? help???