more than friends? confused?

Hey all! 
So I started talking to this nurse whose been caring for my dad at a nursing home, at first it was just talking at the workplace and then he asked for my number after a few weeks. We started to text/talk on the phone for a bit and he walked me down to my car on his breaks. He told me he wanted a serious relationship, and that he likes me but makes no effort to really date me. We kissed in his car during one of our conversations. At the end of January we got frisky in the staircase at his job and then we went down to his car and had sex in the backseat. When in the staircase I asked him what we were and he said we're more than friends. The next day when I saw him he was still flirty and seemed into me. Then yesterday he called me around noon saying he was off tonight cause he worked 2 doubles in a row and he wanted to hear my voice and that he misssed me, yet there was a lot of noise in the background and I couldn't hear him well. He called me back about an hour later saying his friends were over playing games and said he missed me once again and asked if I wanted to see him after I left my dad, I told him we'll see. I texted him to see if he wanted to meet up before then and grab something to eat instead cause I might have to take my daughter home and he never replied but called me 3 hours later saying he fell back to sleep and asking if I wanted to come over and to bring my friend cause his friend was over and I thought it'll be weird so I wasn't very comfortable with that. I got annoyed at him about it and he asked me if I was ok and I told him no but he never answered his text or returned my phone call. I honestly don't get what we are or what he really wants. Can anyone help me please, I'm so confused.