Your soap would probably have been fine if you'd given it more time. It's too bad you didn't ask us for advice before you threw it out.
The most likely issue -- Hot process soap batter can become very firm at first as saponification is ramping up. That's pretty common, and the soap eventually relaxes and becomes nicely stirrable if given a little more time for the chemical reaction to settle.
Another possibility -- HP batter will also firm up if you add cool ingredients to the soap batter. If you add ingredients after trace, they really should be warmed first.
If you want better advice, however, please share your recipe, all ingredients all in weights -- don't leave anything out and don't mix percentages and weights. Also an outline of the method you used would also help.