I have a 2 1/2 yr old with a speech delay (but progressing everyday ;one month ago vocab of 20 words now vocab of 100 words),likes to play with his hands(waves 1 hand alot while laughing/babbling and counts numbers on fingers), likes to be around kids (runs around with them BUT not interactive play), lovable (gives kisses and hugs),makes eye contact when spoken to, prone to tantrums lately (esp. when we don't understand him, when holding new sibling, and at times for no reason).I've talked to the pediatrician who is not concerned. Says he will develop at his own speed. The lack of language (yes, we are in speech therapy), the odd hand gestures, and the tantrums concern me. Do I need to be??