Hi everyone, I have an update. You were all definitely right about the cycling process. I tested my water just now and the ammonia levels read between 0.25 and 0.5, nitrites were around 0.25, and nitrates were at 5. I've never seen these numbers before they're usually around zero. I did a 50% water change and now the ammonia reads somewhere between 0 and 0.25 (hard to tell because of the light), nitrates are back to 0 and nitrates seem to be somewhere between 0 and 5 (nearly 0 but not quite perfectly yellow).
I'll try to get in touch with the fish store that's a bit far away but so far my plan of action is to do 50% water changes daily, the fish don't really get too stressed by it and I get to clean the gravel at the same time. And also using Prime. Hopefully this helps.
Thank you to everyone for your replies!