Welcome to HCM
We understand your concerns
I went through your problem description. You lose the feeling around the head of your penis while you sit in upright position in your wheel chair and this is obvious only during last few days.
Note the word obvious. Means you are noticing it only these days. It might have been there for so many days. This could be so common for you to notice.
Any way do consult your physician for further clarification. You should clarify your doubts without delay to get away with the anxiety
Hope this clears your doubts. Available for further clarifications.