Ex Girlfriend being distant, cold, and lashed out at me for no reason last night?

Long story short we dated for a year and a half. She broke up with me two and a half months ago after I got mad at her(rather not say). We stayed "talking" and made it clear for now we're just friends. Last Friday sense she got her tattoo she's been really distant by text. She's not saying good morning to me anymore, and she replies to my text every 5mins, 10mins, 15mins, 30mins, and the other day she didn't reply to my goodbye text(I was going to work) 4 hours. I'm not being clingy or anything I've just notice that she's not texting me as much as she use too. We were very close to each other when we were girlfriend and boyfriend. I admit I was clingy, selfish, had anger issues and controlling. I don't know why I didn't see it when we were dating but I did when she ended it. The last two months I've been working on my self and I'm better person then I was two months ago. I'm the one who starts the conversations now, and she doesn't even say bye to me anymore. I wanted to talk to her yesterday on the phone. So I texted "Hey" she replied with "Hey" back. I ask is she able to talk? She replied back with "Like talk on phone or text." When she texts me and ends the sentence with a period it means shes mad. I said "phone", and she texted me back with "I don't want to talk on the phon." Well I said it was important. She called me and said "what do you need" in a mad angry yelling at me tone. I did nothing wrong. I got quiet after she lashed out at me.