Yes, yes it is. Among the major Abrahamic religions gambling is an insult to God since you are putting your faith in chance rather than God.It is also sometimes considered usury.
Don't worry though, many of the things you do everyday are considered abominations. Things like eating anything from the water without fins. Or failing to shave the head of a woman without a veil. We live in a time when you can do whatever you want and easily find another person who thinks God is fine with that.