First get off the birth control. Depending on your body and how long you were on it. It may take some time to get back to your normal emotional baseline. If after a month you don't feel like the mood swings are any less...then I would go see a psych professional.
Also, a question? I know those closest to us often unfortunately sometimes bare the brunt of the worst of us, but do these mood swings only happen involving your husband?
If I miss read please excuse that last question...but if not...I'm curious....
Besides the birth control did anything else happen or change in your relationship when these mood swings started?
Last question and you don't need to answer this if your uncomfortable...how old are you?..the only reason I ask is because some personality, mood, and psychotic disorders statistically tend to "crop up" in certain age brackets. And also some people go undiagnosed or misdiagnosed until later than the normal age bracket because some symptoms may be mild and then exasperate at a later age or "perfect storm"...by which I mean a combo of stressors and underlying unnoticed/bottled up/ or undealt with previous traumas or issues...just some thoughts to chew on. Hope it's just a bad birth control reaction tho and whatever the cause turns out to be...please be forgiving and kind with yourself ...because you are not a horrible abusive person. The fact that you are aware of and able to admit to and own your behaviour and you seem to genuinely feel remorse and ashamed and shocked by your actions. That means you are a good person who is going thru a rough time and haven't handled it well. And now that you are aware of all of these things you can get help with figuring out other healthier ways to cope with emotional disregulation. So no you are not a horrible abusive person...please do not resign yourself to such a heavy label. You can beat what ever this is!