Hello and welcome Confused.
You have already heard some of the best inputs. I'm going to re-quote one of Debi's points as it represents exactly how I encounter psychic messages too...
"That's essentially how this works. You will have no warning and for the most part no control on how or when you receive information."
I've been receiving psychic info for nearly 40 years. For me at least, one thing that has been true is that I often receive my info either as I awake or within the first 15-30 minutes of being awake. That is not to say that I don't receive info while I'm asleep or fully awake - because I do. But a huge percentage of it happens during that short period of early wakefulness.
And to the best of my knowledge Confused, I didn't make that happen. It just happens to be true for me. So though I don't have any conscious control that allows me to fully block out receipt of all psychic message, I have (so far) been rewarded by the fact that I can expect that I'm most likely to be a receptor in the mornings.
It is possible too that you are receiving different kinds of info which can at times make it more difficult to recognize the information as being psychic message. Let me offer this example - most of my experiences are telepathic, precognitive, or empathic but not to the exclusion of other forms of perception. For example, I once clearly heard a message - I heard it aloud; and, I was completely alone, in a very quiet sheltered place in the very early morning. Within a few seconds, the receipt of that audible message was confirmed by an incoming telephone call. I think that is called clairaudience. But I would not describe myself as "having clairaudience skills" because I only seemed to have experienced it once. My point is, though it only happened once, it did in fact happen; and, it was just as psychic and valid a form of receipt as the other telepathic abilities that have received many hundreds (maybe a thousand) messages . But I would have easily dismissed the supposed audio message as being non-psychic had it not been confirmed by that related telephone call.
So keep yourself open to any labels you or others might try to apply. Most important, there is a very real chance that you are not crazy.
Editing to add - I don't know that I have any experience with mediumship though in that I'm not certain any dead person or non-living entity has ever attempted to deliver a message to me. Seems to be only the living that I can read along with messages I assume the "universe" is planting into my head.