Is he interested? Getting ALOT of mixed signals - both male and female opinions REALLY needed!!!?

This is a long one, but I REALLY need some advice here, I’m lost! In the beginning of the summer I was a little interested in this guy at work, but he had a GF and I don’t mess with that, and I had just gotten out of a 5 year relationship myself so I wasn’t quite ready to start dating. 2 months ago he broke up with the girl (they were together 2 or 3 years), and I became interested again. A month ago a co-worker took it upon herself to tell him I was interested (I never would have said anything myself, I’m kind of shy at first…and I never told her to do that she just took it upon herself). She said he seemed pleasantly surprised. The next time he saw me he followed me outside on my break & we chatted, just BS. Since then he goes out of his way to talk to me at work (he works on the other side of the bldg), & it's never me approaching him (I tend to keep my guard up at work because of my boss is a jerk, and the guy knows this, told him about it)…and theres always that good eye contact.