Well really...there are only 2 kinds of barley: ones that grow in an arrangement of 2-rows or ones that grow in 6-rows. Hence why many of our malts like to say they are 2-row (which is more preferable for the brewer).
Now, yes, with crystal malts, they don't have many enzymes for mashing. Do you know what Lovibond rating your crystal was? The darker the lovibond, the more the 2-row malt was "stewed" and kilned (which caramelizes sugars that gets converted: rendering them unfermentable). With the lighter crystals, there can be some slight chance of having some fermentables, but it's still nothing like your base grain (just regular malted 2-row).
But the main thing I'd double check on is what kind of oatmeal you used. Did you use flaked oatmeal? If so, you should do OK: the other varieties of oatmeal tend to need some cooking. The other thing is that oatmeal itself is adding oils to the beer to add body and mouthfeel: don't expect an oatmeal taste.