What do you think about single mothers who go to college?

Here's the deal:

I am a single mom and I go to school, I also work 40 hours a week. I'm trying to gage what society thinks about people like me. I feel like I'm doing the right thing by getting an education, some of my family members have condemned me for not being there for my kids, and this makes me a neglectful and selfish mother. I have to admit that I do not see my children nearly as often as I like, and I do feel guilty for missing a lot, and not being able to nurture them like I want. I also feel though like our standard of living will never be better, and they will never have better opportunities unless I get an education, so to me I guess It's not a black and white issue but varying shades of gray. So am I a monster for putting my kids through this, or am i good mom with the future in mind?