Transient pain

N.B. - Pretty good!  If this were spoken it would be nearly perfect, but are  some minor improvements to make with the formalities of writing.  Remember "I" is always capitalized.  This is important.  Also, there is always a space after a comma in English.  There is almost always a comma before "but" too.   Connect two complete related sentences with a semi-colon.  A comma can't do that.  The first letter after a colon is capitalized. 

Transient pain

Your tense is a bit confused in this paragraph. Mostly you used the present tense ('I'm in the city centre') but then later you started using the past tense without any transition. In the above, I've made it consistently present tense.

That sudden deafness which that I enjoyed and those injuries on my knees which that I couldn't feel, unexpectedly relieved me! Re: 'injuries on my knees', it's unclear whether you're talking about not being able to feel the initial impact of falling on your knees, or the bruises you have afterwards. 

Is it my brain playing me some wicked game with me?
My eyes shut and I lost all my senses and I dove into an endless dark sea. I couldn't reach the surface and I started to suffocate, just as if like my body were trying to get rid of my soul!
I could hear my heart beating so fast, the blood running through in my veins, the sweat droplets washing my skin. Usually you'd say 'AND sweat droplets washing my skin' here, but the use of a comma instead is emotive so I haven't corrected it.
It was agonizing, until I tasted that sweet cube melting on my tongue, and felt my body got lifted by those strong, muscled arms!
A voice said: "Don't worry guys, she had hypoglycemia"...

Sounds horrible. Not nice for this to happen in the city. I think you've described the experience extremely well, but you need to be careful with your tense. Also, as a narrative, it's sometimes a bit inconsistent re your state of consciousness.