I had something similar happen with someone I'd known since college. I kept showing up, remembering the details they'd shared months earlier, texting first every single time. Then one day I just stopped initiating anything - and nothing happened. Radio silence for weeks. It stung, but it also told me everything I needed to know. The friendship had already shifted; I just hadn't wanted to see it.
What you're describing isn't paranoia at all. Eight years is a long relationship, sure, but that doesn't mean it's obligated to stay the same forever or that you owe it your emotional labor indefinitely. The pattern you're noticing - always being the one to reach out, them being conveniently unavailable when you need support, conversations pivoting back to them - that's real and worth taking seriously. It's not about keeping a friendship alive at your own expense.
Before you write it off completely, you could try one thing: pull back for a bit and see what happens. Don't ghost or get bitter about it, just stop being the engine that drives everything. Give them space to miss you or prove they value the friendship enough to meet you halfway. Some people genuinely don't realize they've fallen into a pattern where they're taking and taking. Others will simply accept the new arrangement and disappear. Either way, you'll have clarity. And that clarity matters more than spending another eight years pouring into something that's become empty on their end.