my bf(23M) gets these severe episodes of depression every few months. 

The depression appears out of nowhere with no warning then goes away on its own within 2-3 weeks. But he gets it very severe, he gets unable to get out of bed, respond properly, leave his room, eat and sleep lots. 

He is not diagnosed yet. Will see a psychiatrist as soon as current episode gets over.

ABOUT US: 

we have been together for 4.5 years now. we have been mostly in a long-distance relationship stuck in studies, work, and trying to make something out of our lives. while it sucks at times, we have found ways to work around it. There is a specific time of day that we keep for each other and be in contact and regularly/daily.

ABOUT HIM: 

He is currently going through the most severe depressive episode to date, it has been 2 weeks and it's not getting any better. He would eat previously upon me insisting but currently, he is eating little after a 24-36 hour time period while sleeping 12-14 hours a day and staying in bed all day doing nothing because he says "he doesn't have any energy to do anything". HE is unable to even reply to me properly, conversations aside. 

I NEED ADVICE as to how to be helpful to him in a meaningful way? it hurts my heart seeing him like this. 

\-I recently came across a post which stated that people with depressions have to hear things that can feel toxic to them. it included saying the phrase "it will all get better, it's just a phase". I say this to him because felt like it's important to remind him that, it might give him hope. So what are the thing can say which can sound meaningful to him while trying to make conversation with him? -I have realized that it is important to give him space(he asks for it) and not ask about things constantly, this time I have been doing just that, we talk only 15-20 mins a day when he feels like it. But a few days ago he got very anxious all of a sudden while talking to me, upon asking he said he feels numb all day but when he talks to me he feels this rush of emotions which results in anxiety. can anyone decode this for me? -yesterday while him being extremely down i tried to advise him on ways to make days a lil better, e.g. trying to go out, keeping something to eat by his side table, getting some sunlight while showering him with phrases full of love, he got very silent. i asked if i should stop, he said "yes, it's getting very overwhelming" Idk what happened to him but he left after few minutes. can someone tell me how he might have been feeling? what i said wrong? what could i have said instead?  

ABOUT ME: (22F) 

if there is a person who lives with a similar person, how do you stop yourself from getting into the hole of depression yourself?

As i said talking to him is routine. As much as i love to talk to him, its also become a habit. when he suddenly stops talking i experience withdrawal symptoms like anxiety, lack of focus, restlessness, feeling of depression, difficulty falling asleep and doing everyday chores. While they start to settle after a few weeks depression stays.I have been trying to keep my mood up but can't keep myself from feeling down lately. Along with that i can't help but feel frustrated, heartbroken, empty. 

tl;dr my bf is going through depressive episode. i am unable to help him or myself. would need to get advice who experience this closely.