Rolling can be tricky.
You've found out the hard way when and when you shouldn't roll.
Light rolling in the ITB would probably be ok, it's the really deep, shit-your-pants, rolling you shouldn't do before training.
In addition, if you do any "hot" recovery methods, that's a good time to roll as well (sauna, whirlpool, even hot morning shower).
If you're doing a full body session, I recommend starting with the golf ball on the feet, and then working your way up.