Talking to Ex after 7 months no contact...

My ex immigrated a year and a half ago and things were really bad back then. We were not together anymore as it wouldn't work out and decided to stay friends. Things were really good but she then started acting rude and cold. I decided to take sometime away from her, she agreed. Three weeks later I contacted her and she never replied. Cut me off for 7 months.

Four months ago I text her and she replied. We started talking again. She was nice. She sent me a book that I always wanted to buy. But sometimes, she would just get mad at me over literally nothing. She would act so cold and rude. She would just stop replying and ignore me, despite her being the one who started a fight or something. I sent her a gift a few days back. She was so excited all week about getting it. When it finally arrived, she had to go pick it up from the carrier. She sounded way less excited. And she got mad at me when all I said was "I see". She was telling me that she doesn't have time to pick it up anytime soon and so I replied "I see". She got mad at me.

Her roommate finally picked up the gift two days ago and yesterday she told me sh was staying over her mom's place and thus haven't seen the gift yet. She then told me "now you should reply I see". I told her I just thought of checking if she got the gift or not yet.

I really don't understand her or why she's being like that most of the time and I dunno what to do. She mostly starts the conversations, and she's nice at first, but she goes cold and rude whenever she gets the chance, and this whole gift thing is just weird.