Did he use me for my virginity?

I'm 19 and basically just wasn't ready for until recently. I was dating someone about a month ago and after what was admittedly a short while, we slept together. A couple of days later he broke up with me, citing that he was just too busy to have a girlfriend at the moment. I've now found out that he is in fact seeing someone else and is obviously not too busy. I know there is a chance that he just felt that the relationship wasn't working but came up with an excuse instead of the truth, but a couple of people have said that is seems to them he just used me for my virginity. If it is the case I know there isn't anything I can do about it...what's done is done. But it's not a nice feeling, you know? I'm worried that I'm obsessing over him a little bit as well. It's kind of difficult because I have to see him almost every day at work (we're not colleagues, he does some of our deliveries), and it's just kind of hard for me to think that he would do that...He said he still wanted to be friends and for a few days we texted a little bit and now he just completely ignores me and it's kind of hurtful. What do you guys think?