A follow-up information… just found out that the day when the comments stopped showing (5 days ago) was the same day I installed 2 plugins… Ultimate Security Checker and WP-Sentinel.
The first didnt work, gave me an error message, then I left it deactivated. WP-Sentinel worked fine, and since then is protecting my blog from some attacks that happen once in a while.
Tried deactivating both and uninstalling them, but the comments never came back.
