So this is your first Fan Fiction right? I'm going to be a little harsh here, so don't get discouraged, so let's start now. BTW, this is my first review, so I might not make sense.
Ok, when you try to type your story, try to space out your stories, because that from quickly looking at this, it's just one paragraph. That's not even proper indenting and just reading one paragraph of a story is pretty annoying. And try to space out the title from the actual story.
This starts off with lacking detail. You should have given imagery in this, because it looks rushed. Give imagery at where he starts off and what he does, even when he tries to go and wake up his mom by saying "I rushed off towards my mom's room in a flash. Feeling delirious like a Chimchar, I then continuously shake my mom's body like if I were molding clay."
It looks as if it was typed in less than a minute. And give information on Jay, because we don't know who he is or about his backstory a bit. Also, you have a spelling error. It should be "realized".
“Hey, guys! Want to have a 2 on 2 battle” J.R exclaimed.
He had always been a fast runner (and talker for that matter). So it was 2 on 2. Me and Relah VS. J.R and Rebecca!
Okay, format this correctly, because it's unnecessary for parenthesizing the words. You should have said: "He's always been a very fast runner, like if you would challenge in a race, you would see him sprint like a Jolteon. And he's always a big mouth that's like a leaking faucet."
This shows lack of emotion while doing battling. You should have typed on how Relah and Oshawott felt when the fiery, raging blast of Deino was about to reach to them. And how it ends is totally uninteresting with it. It's not a cliffhanger.
Overall, I see that you do have potential there, but it needs a lot of work, let me repeat them again:
Mainly you need to indent and format your sentences correctly, because reading a block as a page is a total eyesore. Also, work on the grammar and the tenses. Had is past, as in before it happened, and Has is present, as in right now.
Next, try to add vividness, because reading your story is very boring. I mean really, who wants to read:
To be honest, but I wasn't really hooked into this story, I mean, it's just a regular story. Many people might find it that too just from reading this. Also, levels are not in Fan Fictions, you're typing this as if it was a game or something. I'm not trying to say that you're a bad writer, but you need to improve a lot, then I'll try to look at this again.
Head on the Writer's Lounge because that there are a few threads that can totally help your problems. And one more thing, try to look at other people's fan fictions and see on how they did it, because it can really help.