If you have had a lay-off from the bike for a while, what might seem like "stretching" to reach the handlebars right now might not really be too long. I always find that after some time off the bike, it takes a few days of riding for the muscles to re-adapt. For the same reason, your saddle might be Ok, but your leg muscles might need to stretch again. So you unconsciously compensate by riding more forward on the saddle (which has the effect of making your saddle height effectively lower).