My first AIBU - I'll try to keep it as short as possible without drip feeding.
I write to somebody on death row in the US. We've been corresponding for just over 2 years now, and we're very close. He has no family so I'm pretty much his only contact in the outside world.
A while ago I was signed off my uni course with severe depression that totally floored me. I ended up being off for several months. During that time I was in no state to write, and I also had to move house so he couldn't get in touch with me. I finally wrote back, apologised unreservedly - he had been very upset and worried about me but accepted my apology and we moved on.
Now I'm back at work and while I know it's been the right decision, it's left me exhausted and really struggling to get back into a routine. For that reason writing took a back seat again, and it was longer than it would have been before I managed to send a letter. I did send one, though, and he'll now have received it.
However, we crossed letters. I've had one from him again expressing worry (and annoyance, but mostly worry) - he's had a really tough time and not hearing from me has added to his stress. 
I'm considering whether it might be fair in my next letter to express surprise that he didn't get the postcard I sent apologising for the delay and letting him know I'd be back in touch soon. Except there was no postcard.
On the one hand, believing that something got lost in the post would make him happy that I'd been thinking of him and that our correspondence meant a lot to me (which it genuinely does!). On the other, he's been lied to and messed around enough already and I'd feel incredibly guilty not being straight with him. Either way, this is about making him feel better, not assuaging my guilt.
WWYD? I'd like honest opinions, but please don't come on just to tell me what a shit friend I've been - I know that already.