Please help!

My boyfriend and i have been going out for 18months, he suffers from depression and recently when he's low he tells me he doesnt love me and doesnt want to be with me, he then ignores me wont reply to textes wont answer my calls etc normally the next day he apologises and says he didnt mean it and he does love me. But today he is still really low and keeps saying he doesnt love me, im soo confused and so emotional and dont no what to do, i no he loves me he always talks about our future and doing loads of different things together im just soo confused and upset right now i need some advice!