I've known my friend for about nine years. We got on well, and were very close. For the past four years or so she's had a really tough time with her mental health, and I've tried my best to support her with that. It was especially hard for her during the first six months of 2018. She was feeling very low and her boyfriend broke up with her rather unexpectedly. I tried to be there for her and help her, emotionally and practically, but somewhere along the way I lost myself in caring for her. I gave too much of myself, although I didn't realise it at the time, because I'm a caring person and felt that I should do what I could to help. It's only looking back that I can see our friendship wasn't entirely healthy.
I didn't really hear from her between June and August because she needed some time to herself, and honestly I needed it too. We reconvened at the end of August/start of September and things were okay between us. I met up with her a couple of times in September and October, but I haven't seen her since then. We sent each other the odd message or two but I haven't texted her since Christmas, and she hadn't contacted me either.
She sent me a message last night out of the blue, asking how I am and apologising for the fact that it's been so long. I haven't replied yet, and I don't know what to do. In the time that I haven't seen her, I've been working through a lot of stuff from my past in counselling and so I'm generally feeling quite raw and vulnerable. As well as that, if I'm honest, I feel hurt surrounding our friendship, some of which is my own doing by giving too much of myself, but also because I've felt a bit neglected by her and like I've been making all the effort. I feel like an elastic band which has been overstretched and can't just snap back into place. I haven't told my friend that I feel hurt because I know she's already struggling so much and I don't want to make it worse. But at the same time, ignoring the fact that I feel hurt hasn't made it go away, and she's my longest friend and I really did value our friendship. I don't think she has any idea about how I feel. Should I be honest with her? Because I don't think I can carry on pretending that everything's fine, but honestly I don't feel strong enough at the minute to address the issues.