Bf embarrassed of me

I feel my bf is embarrassed to be with me like he does mx and he was with his mates and the track on training day and we’ve been dating for 9 months now and I was leaving to go make lunch with his mom for him and as I left I said I love u and he didn’t say it back he just stared at me. For a few seconds I came back and I asked why he didn’t and he said cause there were people around and he always tells me to stop kissing his neck or hugging him cause there are people around I’ve tried talking to him but what do u guys think it’s making me really insecure and he’s said stuff like when ur older can u not be fat., referring to me being fat now so I am on a diet and reducing my eating and he never shows me support in anything I do