Just got my pen BUT IM SCARED

Hiya, looking for some encouragement.... Had a horrific past 6 months emotionally/physically and gained over 40lbs quite quickly... I received my pen and it's in the fridge, I'm scared to start because of potential side effects. Is there anything you guys can suggest. I'm trying to make sure I have supplies of things I might need like gaviscon in case I get indigestion or paracetamol and pain relief for headaches and body aches... I'm also making sure I have some electrolytes. I just feel a bit nervous to do the first jab in case it wipes me out or something or I get nausea.

Has anyone done it and just been ok? I am trying to psych myself up to do the jab tonight.. are there any times of day you've felt have been better or worse or injection sites? Any advice?

I'm 170 cm tall, 82 kg and have a waist that's 42 inches currently. PCOS 36 years old. This is the worst I've felt in a long time and am desperate to kick start some health and self care. I plan on getting to the gym as well as using the medication.

Any words of encouragement or support are very welcomed.