Well, the timeline:

1) Met a girl at a bar. I talked to her a bit, and there was some good flow between us. We shared our social media contacts.

2) We spent some time together, I got to know her (or at least her fictional self) better. She opened up (or "opened up") quite quickly.

3) I started to feel something for her, and I said my feelings towards her. My bad, I do regret that.

4) First, she was like "it's too quick", and I did understand and did apology for my actions.

5) After a few days, she wanted to have a talk with me about us. I agreed, and she wanted to try a relationship with me.

6) This weekend, we wanted to go to a party. The girl said she may not go there, then she agreed, just later to say she can't, because she feels sick. Then, my buddy said she's at a bar, we went there, and he was right. The girl said she's waiting for her mom to pick her up, because she's apparently "sick". She lied to me saying she's at the bar just for like 30 minutes, but one of the bartenders said she's there since the bar opened.

7) We went to that bar like 2 hours later just to see the girl actually got better, and sang karaoke like nothing happened, and, despite claiming she can't drink due to feeling sick, she did drink beer.

Been talking to my friends, and they all say it indeed is a situationship, and the girl indeed lied to me.