Habits Only Accessible Automatically?

Here's a strange phenomenon that confuses me: Have you ever had an ability, habit, or the likes that could only be accessed subconsciously, making it impossible to consciously control?

For instance, at one point I managed to type my e-mail password purely by muscle memory, and I sustained that habit for several weeks, if not months. One day I wondered what my password was in explicit terms, and to my surprise I couldn't figure it out no matter how long I thought, and there was no written documentation of it. That was actually enough to erase my muscle memory habit, so I couldn't access my e-mail for several days, maybe weeks.

Another example would be my speaking habits. When I speak to other people in person everything is absolutely fine, pacing and all. However, when I try to leave a message on the phone or read aloud to myself then I take on an artificial tone, can't control my breathing correctly (often trying to say everything in one breath), might speak too fast or too slow, and so on. Yet, when I pay attention to my speech when talking to people everything seems and feels natural, so I only run into these oddities if I'm by myself.

Of course, there's nothing wrong with integrating a habit so deeply that it becomes subconsciously embedded, but my worry is in how I can't seem to reverse the process and bring things into my conscious awareness. I typed my e-mail password flawlessly before, but lost all record of it in my being when I thought about it, and my speaking goes all wonky anytime I'm not talking to a live person.

This reminds me of those cartoons where a character would be able to pull off amazing feats they couldn't while awake, like the popular scenario of a sleepwalker wandering into a construction zone and pulling off acrobatic feats amongst the steel beams and wires, and upon waking they start to lose balance and freak out.

Has there been any formal research on this? Has anyone else had any similar experiences in this realm?