It could be the rebound effect but if its still ongoing and you haven't been on them a while then it could also be your oestrogen levels causing excess adrenaline to pump out to keep your heart beating adequately, particularly if you get it early morning and late afternoon (2-6pm roughly) when natural adrenaline peaks.
It caused incredible shaking, overwhelming energy racing through my body and extreme nausea for me. It was terrifying until I worked out what it was! The pill is keeping mine under control for now but not sure of your HRT options?
The beta blockers will dampen the adrenaline and the ADs may also help indirectly. The source could be low oestrogen though if you would prefer to start there if you have options?
You really are not 'drowning', you are still here - trust me, the words we use get taken literally by the subconscious so that will cause you more panic! You really are surviving but you're also in a hyper alert state because of the adrenaline. I really would take a 10mg BB now and you'll notice in an hour or 2 you will feel less overwhelmed - try to distract yourself whilst you're waiting for it to kick in. I used to call a friend and ask them to chat with me whilst I waited as it was such an unsettling feeling, regardless of knowing whats causing it.
Even if it is rebound from stopping the BBs, having one now and again will then be a gentle way of coming off of them. You have not messed up your system as levels will ALWAYS fall back to normal once you stop whatever you took for long enough. ADs can make you feel worse before you feel better, so that may also not be helping.
Perhaps sit down later with your husband and tell him that he really disappointed you by thinking you were seeking attention and that's why you ignored him. He's probably a bit lost with it all and keeps putting his foot in it saying the wrong thing! To put it mildly. Hopefully, its not coming from a negative place, just ignorance. Try to be assertive with him (less emotional, so neither aggressive nor passive) so that he can clearly understand your concerns and explain that many women suffer in the same way but most of us don't have them in our circle of friends as it is an extreme hormonal imbalance, not just classic menopause.
You'll get through this, don't worry!