Should I be mad if my friend didn't invite me somewhere?

Okay, so I found out that my friend, let's say her name is Amanda which obviously isn't her real name, didn't invite me to the movies but she invited everyone else in our, well I guess you could call it our little group of friends. I texted her saying "Thanks 4 inviting me 2 the movies.." then I texted her again when she didn't answer telling her that I knew she had her phone on an that she got my message but she was just to scared to talk to me. Then a little while later Amanda texted me back saying "I didn't think you liked the kind of movie we were seeing and it was a last minute thing and didn't think you'd be ready". Now I originally found out about this from my other friend, let's call this one's name is Gianna, accidentally telling me about it because she automatically thought Amanda had invited me too. So Gianna explained to me that Amanda invited her saying that she knew she wasn't really into the kind of movie they were going to see but she didn't want her to feel left out. And in the last text I got from Amanda she said she knew I didn't like that kind of movie either, but obviously still didn't invite me. Then, in response to that text I said "You invited Gianna and you knew she didn't like that kind of stuff and you said you didn't want her to feel left out, but whatever..." Now Gianna is telling me I'm over reacting, and what I want you guys to tell me is, am I? I'll admit I don't invite all my friends everywhere I go but this is different, she invited everyone in our group of friends expect for me. I felt really hurt and left out. Should I feel bad/angry because of what Amanda did to me? Or am I really just overreacting?