The introduction draws me in wondering what's going on next. Each line brings up questions, and is answered in increments. It does feel tense.
In the first two sentences there are places where it needed words like (hoping) to get (a) message reply (to) my
And instead of telling I would show the person is worried. Think about physical things that indicate they are tense, scared or worried.
Do they bite their lip, sweat, pace, tap their fingers, bite their nails, fidget, or organise items on thier desk?
This helps the reader to envision the condition of the worrier. It also build tension.
*Example: I glance at the clock It's 2:00 a.m. Instead of sleeping, I'm awake. My skin feels sticky. I bite off the last bit of a hangnail on my pinky finger. I wonder if my pacing has worn patterns into the floor.
Sinking into a chair I stare at the blurring shadows of inanimate items in the room.
My last thoughts were Why has he not called? My eyes betray me as they slide closed. Just a few seconds of bliss.
Here is your version with a few edits.band some dialogue.--
I always worry if I haven't (heard) from him, because I know (of) his condition.
Heres my rewrite: The phone rings, my body jerks forward. My eyes pop open, I focus on the phone in my lap. It's him. "Hello? What happened? Are you okay? I've been a nervous wreck waiting."
"I'm exhausted. I haven't slept in three days. Nothing helps."
"How are you feeling now?"
"Anything else? Ive been waiting for yur call."
I've got pains in my chest."
I knew he had tried many cures for insomnia without having positive results--warm milk, chamomile tea, and melatonin capsules. "You need to see a doctor. This isn't good. You need one now," I say.
"I'm sorry I didnt all. I couldn't. It's difficult to move around at the moment."
"I don't feel good about this."
He hesitated. "Don't worry. I'll be okay soon. I always am. In fact im starting to feel better already."
"I will pray for you. Please call for an ambulance if it happens again."
** I hope you get the idea with my examples. Feel free to use them or your own.
With some changes, dialogue, description and additional information you could build on this hint of a premise. We want to know more about these two people. We ant o know where they are in life, what they may have experienced, and what they d at this time.
Y yo u need to break up large paragraphs with a single line space between them.
Continue to write even if it needs revision. Let your imagination soar.
Thanks for sharing.