When I'm around others, I try to repress and mask my emotion/mood swings by numbing myself in order to seem 'normal' to prevent others from thinking something is wrong with me.

However, once I'm alone in my room (especially at night), I bounce around between emotions a lot at times. I can go from being somewhat destructive (punching furniture/hitting things from anger) to being sad about my situation (even though I shouldn't be) and tearing up, to then matching the happiness of the music I'm listening to, etc.

I feel like I'm faking things, like I want to make up these mood swings to justify me being messed up even though I don't 'want' to be messed up (or at least I think so... I can't even tell anymore). Whenever I want to explain things to family or a therapist, I'm back to being 'normal' and my numbness helps mask any mood swings or extreme thoughts (Such as them hating me, only hanging out due to pity, not taking me seriously, or that I'm not worth any love, etc.) so it becomes extremely hard to discuss things with them.

I swap from being happy ("How was I ever sad/depressed about this? It made no sense.") to feeling hopeless and worthless ("How was I every happy? Was I actually feeling enjoyment from gaming/watching tv? How do I get back to it?").

I bounce back and forth when alone, but then stabalize when around others as sort of a defense mechanism. I don't want to seem like I'm heading to the deep end of depression/suicidal thoughts again, so I act normal until I FEEL normal. But once I swing back to that dark corner, I want to express myself, to let others know I'm struggling to keep my sanity in order, but part of me doesn't want to let others know because I'll just swing back to being happy and 'normal' again.

Is this a common experience with BPD or am I experiencing something else? I don't want to talk with family about it or mental health professionals because I don't want to worry others about my on and off problems (Mainly because I always hear the "we all get that from time to time" excuse which makes me isolate myself more).

I'm not asking for a diagnosis or anything of the sort, I just want to know if that's... something others around here experience as well. I'm getting better at hiding it, but I still dissociate a lot and can be influenced by mood swings very heavily at times (Even for mundane tasks. I remember one time I had trouble mopping the floor (something I've done before easily) and started crying and getting super emotional, then being fine the next minute).