Contraceptive injection

I have only been on the combined pill for a matter of a couple weeks but so far i am not loving it. I feel like i am starting to gain weight and i feel super bloated and rubbish, as well as a few other things. I am also absolutely awful at remembering to take it!!😂

I want to try the injection, it just scares me that you cannot get it out of your system for 3 months. My step-mum had a 3 month long period which is not something i want 😟😂however i know my mum uses it and has no issues. Am i likely to have no issues because my mum doesn’t, or would that not relate?? I really want some advice, has people had any bad experiences with it or is it often positive? Thanks in advance :) xx