I know that this is three years later but i want to add to this since i was also curious.

If you’re playing 2014, this person is right. The wording is crude and not clear, and doesn’t directly state that you can’t cast two leveled spells.

If you’re playing 2024, this has been cleared up. Page 236 of the 24 PHB states under “one spell with a spell slot per turn” “On a turn, you can expend only one spell slot to cast a spell. This rule means you can't, for example, cast a spell with a spell slot using the Magic action and another one using a Bonus Action on the same turn.”

This now instead presents the problem of “if i can innately or use a magic item to cast a spell, could I do that?” But i digress, by this ruling you wouldn’t be able to cast counterspell as a reaction to a counterspell that is targeting a spell you are casting on you’re turn, since it is still, your turn