yes, carving out something for yourself is an important first step.
DOn't think the first thing you decide has to be "right", I mean how can you know if you don't try?
I started with a creative writing course and volunteering at a local sports club (some bar/bbq work), the creative writing wasn't for me, but hey, I lost nothing in trying something new. And I had a few fun stories to tell afterwards as well. I met some really nice people at the sports club 9where my kids go) and had a good laugh doing the bbq with some of the other parents (hard work, stinky clothes, but we brought some beers along and had a laugh as well).
Then I started telling people I was looking for a job, just spreading the word helped. through friends of friends I was asked to do some translation work. After half a year the company I worked for went bust! (architects, it's the economy). Anyway, it got me a recent work reference which I realised was essential when looking for a job. So even though it led to nothing it was still worthwhile.
I also joined a sports club for myself (tennis) and had 2 days a week where it was carved in stone that I went. If the kids had homework/clubs, DH and to deal with it. (DH has 3-4 events a week carved in stone for his hobby, so he could hardly complain. And actually, he did not complain. in my mind I and prepared all these arguments, but he was pleased I was doing more for myself.
Anyhow, then I landed another temporary job, badly paid and it's drying up (only did 3 hours last week) but it has helped my confidence and has given some practical, fresh experience.
Long story, with ups and downs! And more to come, surely. But it shook things up a bit and meant the DH and kids take me (a bit) less for granted.
You can feel terribly unappreciated and invisible as a SAHM, and you have to remind yourself you can change things. Your DH and DSs might like it if you do! (and if not? tough! They will learn to like it)
Just try something out.