I find myself isolating or drawing boundaries

Four times in the last month I've done some isolating. Although I can't tell the difference between it and drawing boundaries for my time. Can someone give a guide on when you're isolating and when you're drawing healthy boundaries?

For me, isolating is when I push people away even as I need them the most. Whether as hostile retaliation [abandonment issues] or when I feel too de-humanised to relate - that I'm a burden on people.
Health boundaries, on the other hand, are for me allowing myself peaceful space to recuperate after a busy day, or giving myself some gentle 'me-time', doing what I need to do to tone down my stress levels.

NB I have depression and complex trauma issues, not Schizoaffective. But I grew up very socially isolated and marginalised, and tend to repeat it if I'm not careful.

I can really relate to the feeling of being a burden. I moved away from the big cities and moved to a small town in the mountains - the ultimate isolation. I have no family or friends here and feel intruded upon if someone even comes to my door. Boundaries can be very thin. Then I use FAcebook and these forums to keep in touch with others, where I can control when I want to interact with someone. It's not the solution as I do need that face to face interaction as well. I know it's not healthy to be alone all the time. I am getting better about going out a couple times a week but it's still hard. I'd rather hide out in my little cottage.