Hi. I'd really like some advice if any of you have experienced something like this??!

So my partner is in the navy. He has been for years; way before we met in 2019. So I knew when I met him that he might have to go away at some point. Now that time has come - he's going away for around 7 months. The longest we've been away from each other in the last 17 months is 6 weeks due to Covid-19 and I don't think there's been a single day we haven't at least said hello. He is everything to me. I fight for him. He can read my emotions better than anyone has ever been able to - as in, miles better. When he is away he will have some wifi he thinks, but idk. If he doesn't we can call I think once a week. 

And my DBT ends the week he leaves (as far as Ik, the navy are vague af) so I'll lose my therapist and my partner in one week. I live with my parents who are supportive but not overly helpful, I have two friends and some more out-of-touch people I need to build better bridges with. I'll also be going into rehab at this time or the month after.  

How do i cope with this?! What do I do?! I'm so scared. 

To be more specific, 
I know I will feel our connection is lost due to less communication so how can I make more use of our limited time on facetime while he's away? 

I will miss him so badly and lose some of my motivation, how can I "replace" this? 

How do I build a support system strong enough to cope with me in only a few months?! I don't think the support system I have would actually support me enough to keep me steady without him.