From what I understand the 2.5 starting dose doesn’t impact everyone or even most people.
It’s a loading dose. It’s not a therapeutic dose for most people. Some are lucky and it has an impact straight away. But not feeling much effect a day and a half in, doesn’t mean it won’t work for you.
You could find that by injection 2 or 3 (so still at 2.5) that it starts kicking in.
There are non responders buts it’s quite rare. There’s no reason to think you would be a non responder.
2.5 has had an impact for me. But I inject on Tuesday and it peaks Friday/ Saturday. By Tuesday I am ready for the next injection. So you could even find in a day or so, you feel a big impact.
Keep going and don’t panic about it not working. Worry about it not working might stress you even more. And stress can slow down weight loss anyway. Good luck