Struggling with meltdowns

I'm just wondering if anyone has advice or has similar experiences when it comes to meltdowns...

Sometimes, when I have a huge meltdown, I end up screaming/shouting really loudly (so loudly that my partner thinks I've injured myself), but I don't really realise I'm doing it at the time. I sort of know I'm screaming/shouting, but I'm not making a conscious choice to do it and it almost feels like I'm detached from myself in that moment. Also, I sometimes throw things (never at people - just at the floor or the wall) and don't always realise I've done it until afterwards. Does anyone else get this?

I'd really appreciate some advice on how to recognise when a meltdown is coming and cope with them better. It's happening almost every day and it absolutely drains my energy - I end up crying for ages (sometimes half an hour, sometimes a couple of hours) and feel like I can't even function at the end of it. I just have to take myself to bed to recover.