She sent me this… what does she mean? Back to her ex or sound honest?

Hey all. I’ve recently been seeing a girl for the past two months and things where going super well. She even stayed at mine two nights ago and was concerned about whether I was into her / said she wanted to stay at mine longer and not go home. Anyways – she sent me this below (keep in mind she told me that her ex sent her a letter a month ago but told me not to worry as she isn’t entertaining it but wanted to be honest with me)

‘You know I got that letter a few weeks ago? Well since then he’s also emailed me lol🙄 And idk if it’s because he’s put things in my mind or what, but it’s put a spanner in the works and I feel confused and in the back of my mind not sure if I’m fully over that yet. I don’t feel it’s fair to potentially mess things up with us as well which I know I will if I’m not fully emotionally available 🙁 It’s so annoying cos I literally can’t fault you haha you’re amazing but I feel like as hard as it is I need to do the right thing and be honest and not carry things on while I’m feeling this way x‘

…. I do think she genuinely liked me a lot, but her saying that surely means that she’s considering her ex again and just wants to sack me off to explore that again? Please let me know what you all think :/

Q: Do you think I was just a rebound all along? Do you think she’ll reach back out if I leave her be?

EDIT: I replied back with the following

‘Okay, thanks for being honest – I knew something was wrong. I’m not one to try and change minds, especially with exes on the scene like that. Hope you get a clearer mind. x‘