If this was me, I would chat to partner about it. Explain (again) that you are trying really hard to make healthy choices and explain that when you fancy a ‘treat’ you are trying to choose fresh fruit, a fancy yoghurt etc.
and also explain you are trying to also enjoy non food ‘treats’ as a way to still treat yourself and indulge. Be specific. A Fancy bubble bath, a nice body cream, a magazine, a new lip balm , a scented candle etc.
im sorry to hear you are in such pain OP, extreme period pain is no fun and it must be really hard to manage that level of pain with a little one to look after too. I imagine that level of pain along with raging hormones and a teething baby have you at the end of your tether, and have made this interaction with your partner feel really frustrating and a bit ‘bigger’ than it might feel if you were feeling well.
you sound like you don’t feel you are being heard, And you are working really hard to eat well and maybe feel a bit sabotaged by him bringing you junk food?
Maybe sitting partner down and directly telling them why you felt frustrated by them bringing you this and offering direct suggestions to them of a more appropriate’ treat’ for you might help?
No idea if your partner is a reasonable sort, but if they are this might help?
im sending you a hug x