Try drilling dry, or with a small air blast to clear the drill often. The heat may help to soften the metal to some extent.
From what drilling I have done in hard materials, I find it necessary to resharpen the drill quite frequently. The best point is the split point grind, because this has almost zero web thickness. It is very difficult for the web of the drill to extrude the hardened material.
A diamond grinding wheel is a necessity for redoing carbide drills versus a green SiC wheel which is next to useless, IMO.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)