Unconditional is a strong claim, and most relationships don't quite meet it. What they do offer is durability — people who would pick up at 2am even after a stretch where you were hard to like.
That durability isn't self-maintaining. It looks automatic because the maintenance happened years ago, in small deposits, and is now running on reserves. Reserves deplete.
There is probably a message sitting in your phone you meant to answer three weeks ago. Not a character flaw. Just drift.
Answer it today. Two sentences is enough. Valuing people and contacting them are supposed to be the same activity.