Adam, my friend, I bet anything that your instructor is ex-military!
Whether or not, it is time for you to fly with somebody different. The instructor who is overloading you and telling you off is probably not very confident himself.
As for radio difficulties, making the transition from gliding to the PPL, this is where glider pilots come unstuck. May I suggest you invest in an airband radio and spend a lot of time listening to the busy frequencies. And if you fly United Airlines, always stay tuned in to Channel 9. The more you listen to the professionals, the more your brain is able to think that way.
And remember, the ATC is there to serve you! The three most useful things I found to say to ATC were "Say again slowly!", "Stand by" and "Unable"!