Feelings after a "temperary break up"

Introduction
Hi all. First of all, my English is not my primary langue so please excuse any grammar errors. I am the one part of a couple. I'm the male, I'm slave, sub, a cuck, a chastity cuck and so on. My Miss and I have played for a few years on and off now.
The past two years we been exploring the cuckold / 24/7 chastity niche inside BDSM, we have only played with random partners and we been playing / stopping / playing stopping for the two years that have passed.

2 months ago Miss met a super Dom male who was seeking a 24/7 Hotwife/slave couple (not live in – but a long relationship). We both jumped at the chance to meet this guy. Miss had a casual meeting with him and he turned out to be absolutely perfect. Extremely dominant towards both of us, almost without any limits, well educated, tall, handsome – the whole package.
He made it very clear to Miss that for him it was his life and he expected the same from us. He wanted us to commit to him 100% and take our BDSM life into our normal day life. This has been a dream for us to do, so we were still game. Of course we were also very nervous, couldn't *****, stopped eating, had trouble to complete our day jobs.

Sadly he had to cancel our first play session due to illness. We were both very sorry and we sadly also lost faith in the whole project. But we couldn't stop the thoughts about him so when he returns from holiday we will try to set up a new meeting.

For the past two months Miss and I have played 24/7 in our Dom/slave roles, I'v been in chastity, no orgasms and its been extremely intense play (like a 24/7 can be).

The problem
A few days ago my Mistress´s mood started to change. It's about a week until her period (menstruation) starts and its absolutely normal that her mood changes. Its been like this for the past 6 years, and I know its normal.
She starts to exclude me, getting pissed over nothing, looses interest in everything and so on. But again – it's a part of her and I know (and love) that part of her.
BUT! Normally I can coop with her mood change, its not pretty but I know how to handle it. This time however its completely different. I feel like I have lost both my Mistress and my girlfriend at the same time. I'm feeling sad, depressed, can't stop thinking bad thoughts (like she doesn't love me and so on). Its not relational at all, I know that we are strong together, and that we love each other. But my feelings are so hurt, we are arguing, and when she has these mood swings she can't coop with my feelings at all.

Is there anyone out there who have tried the same or can give some kind of advise on how to deal with these feelings?

Just a clarification, when she felt the mood swings she decided to remove the chastity device so at the moment its not because of that.