What is going wrong?

Since last week at 3 months and a half Sheraz has been fussier than ever (not to count his growth spurt when he was 3-6 weeks). He can be cranky at times. One moment he's so happy and one moment he can cry and sometimes scream. I thought there must be something. I tried to check his body all over, changed clothes, tried putting him to bed earlier. Nothing seems to be wrong. I thought it could be teething (?) I know he's only 14 weeks old and teething might be too early. But shifting under the gums may has started and it's achy and painful. ( I guess) Some of the symptoms of teething are drooling, wakefulness, crankiness, crying, biting, chewing; and Sheraz is having most of those. He's been drooling since he turned 3 months old and he's been chewing like he's eating something. And most of the time he sucks his hand.

Yesterday he cried and cried. He didn't want milk, didn't want to play or sit on his chair. When I carried he screamed. Since I tought it could be teething so I let him bite his teething toy. And there he took and enjoyed it. Poor him.

One more possibility I can think of is colic. He has been experiencing colic few times. But I just have the feeling that this is different. I hope Sheraz can get over what he's experiencing and I hope I can have more clues and be able to help him.