Is it normal my cousin has done the very thing she said she wouldn't?

I have only known her since November of last year. When we first met, my sis (age 19) me (age 23) and our cousin (age 39), would always hang out.
She's the first extended family memember I felt close to as we would see eachother every weekend. She would text often too like few times per week we would communicate. I would ring her every now & again and we would talk for hours. Time would fly and she said she's never spoken with someone like this before and we have a very special bond. She would say things like no one has ever made her laugh as much as I do, that I'm so funny, thoughtful and/or sweet. I recall her saying once that I'm worried it'll all fizzle out (the relationship she meant) because it was so full on. I thought that genuinely wouldn't happen because of how connected we all felt.

Skip Forward.....

For the last 3-4 monthsshe's gone quite distant on me/us and I don't understand why...
I know she's stepped into work more and always struggled with health but I have been there for her trying to help her.
Up until 3-4 weeks ago I would ask if she would like a call and she's blown me off, saying something along the lines of being busy, or not right now, yet she would never offer a day and/or time for me to ring. I have given up because not only that, but she rarely texts anymore either :/
Once every so often but she won't even ask how I am or what am I upto or want to hang out. it is usually a closed statement eg "Hope you're doing well"
I have even asked her if I've done something wrong and to please tell me and she says nothing at all and don't take it personal...
Any ideas as to what's happened! I feel it's over, I'm not reaching out anymore, been 2 months since I have seen her.
We used to have a blast each time :/