Girl answer please and thank you?

Okay, so I'm talking to this girl right now and I really like her. But I keep getting this feeling in my stomach that says she is talking to someone else. She says she's not but she invited me to her superbowl party so that's a good thing right? But when I left she didn't walk me to the car and said it's to cold. She also haven't came to see me I usually see her once a week and I just don't no what to do. I'm wondering if I should just stop talking to her for a few days. But I dint wanna do that because valentines day is coming up. I wanna tell her how I feel about her that day. I'm just lost :/ what kinda reaction should I make. I don't wanna loose her