One can't predict how their life will turn out even the next minute. We only hold on to hope that life will always treat us well, unfortunately, it doesn't.
In the past you've always strived to help and support your friends in whatever way you can, but now that you're unable to do so, don't beat yourself up. Being a deadbeat friend wasn't what you signed up for - but life happened, and there's nothing you can do about it, at least not now.