Childhood friend of 20 years. We live an hour apart now and we're both busy with family and work etc. She's become quite cold and distant over the last few years. Short replies to texts, doesn't contact me unless I contact her 1st. I've been quite poorly for most of this year and have just started immunotherapy treatment which is going well but has knocked the stuffing out of me. She hasn't checked in at all. It's constantly niggling at me. I'd be there for her if it was the other way around. Should I just let the friendship drift? I feel like I'm flogging a dead horse.