Weight loss

I really want to lose weight but I don't know how being a new mom of a four month old my bf tells me I'm gorgeous beautiful and sexy but I don't feel that way so whenever we go out on constantly comparing myself to other girls and it causes us to fight constantly I really need advice on how to lose weight and how to deal with these caffeine headaches I have no idea what I can and can't eat what exercises to do like i want to focus on my boobs tummy thighs butt and arms and I just don't know how to get started or what to do and I can't afford a personal trainer or anything I'm just desperate I want to feel beautiful in my own body I know setting. Huge weight loss goal isn't great so my goal is 5 lbs in a month at least that way I don't get upset when I don't obtain a bigger goal any help/advise would be lovely