Sorry to hear about your Mum, that will of course be an additional complication in your mental process.
In terms of acceptance, yes it's hard. Try not to tell yourself that though. Lots of things in life are hard, but we just have to get on with it. 'Yeah but'.....is a subtly powerful statement as it's a mental excuse to repeat negative behaviour. That was my experience with it at least.
There's a fine line between filling your time and not being mindful. Sometimes acceptance just means doing nothing and dealing with the consequences. So if you're sitting around doing nothing and you start to feel bad, say to yourself 'so what?'. What's really going to happen? The answer is nothing, it's just sensation. That's a more powerful reaction than immediately distracting yourself with something else, because in the long run it removes a lot of the power of anxiety.