Slow, Fast, and back to Slow

I'm M17 and this girl is F16. Theres this girl that I met on an app about 2 to 3 weeks ago and it was a slow start, but a nice one. We'd text here and there and it'd work out fine. We started playing games together and having fun. I asked her if she wanted to talk over the phone and she was a bit hesitant, but went ahead with it anyway. The first call we had was 8 hours long. Crazy, right? It was an amazing call. We talked about all sorts of things like, past problems, relationships, and just bad experiences. Everything we talked about was relatable. It felt really good to know that there someone who has had problems in their past like I have, so naturally I developed a crush. Now this was my first problem because it felt like an addiction. I wanted to talk just like before the next night, but it only lasted about 4 hours. Not bad. After that, it flatlined quick. We played some more games and we talked while playing. Then I asked if we could do the same thing we did the previous nights and she said she was tired and just wanted to go to sleep. I'm not a douche, so I didn't take it the wrong way. The next day we played some more, but she didnt wanna talk at all this time because she had a headache. (I try not to jump to conclusions, but it happens way too easily) The next day, we texted a little, but she would take a while to respond. It would take her 30 mins to 2 hours to respond.(I text back quick, so there shouldn't be a problem of not seeing it) Half of the time I need to send a meme or something to even get a response. Yesterday I decided to just not text her because she left one of my texts unread. Today she texted "hii" and I deadass felt like leaving it. I decided to text back after like 30 minutes or so saying, "heyy" (My texts are never this dry, but I honestly felt like throwing my phone to begin with because she didn't even mention the text I sent her before it) Then it takes her another 30 minutes to text back "wyd". I've basically had it at this point. Before this, I'd text back within a minute or two, but this totally killed my drive. Idk if I should tell her how it makes me feel, deal with it, or just straight up drop her entirely. I really like(d) her, but it's hard to tell someone how you feel without them feeling bad and just ghosting you. Its happened too many times with me and it sucks. What should I do?