Opening up

I wanna be able to open up to my boyfriend and let him know how I feel whether good bad or indifferent but I'm so used to bottling up my emotions that I'm not sure how to express what I feel unless it's happy things. Sometimes he does things that hurt my feelings or makes me upset. Like yesterday late night we were hungry so I drove to get something to eat but when we got to the place he complained about not wanting anything anymore because It was crowded. The line was out the store halfway down the block. So we left and did nothing except sit in the car for the time we could have been in line. I was annoyed that we just did all of that driving to just turn around and leave without eating. Then we talked about how a friend of mine was rude because she didn't answer a simple question that I texted her. I asked her how to do something. He started jumping down my throat saying I need to learn to figure things out on my own. I had already did it by myself so I wasn't sure why he was trying to make it a big deal. I was just telling him why I felt it was rude. I didn't want it to turn into a debate. Then he told me that he would have ignored me like my friend because he would have felt like Im an adult so I should know how to figure things out on my own. As if adults don't have questions. It just made me feel like he lacked compassion for others which hurt my feelings. I just got extremely upset and wanted to get away from him so It turned awkward. I got off the phone and cried because I really felt hurt. Only I don't know why or how to tell him. He just thinks I'm strange that I'm upset over something so petty. He asked was I mad at him and I just said its whatever and felt myself pushing him away. Now I feel bad because I was wrong to push him away without explaining what had me so upset last night but I don't know why I was upset or what to say or how to begin.