Oh dear... I've noticed it yesterday just before I logged off. Perhaps check out if you've "automatically" started following something else than users. After the last update a month or 2 back, following at least one subject became obliged. So than I had all "girlsaskguys" subject questions in my feed. I got used to it, but in the coming day or 2 I'm gonna try to discover what's new and if it's an improvement or a disappointment. For the moment I'm open minded haha :D
To see the posts only from users you are following, you just have to click the "buddy" icon at the top of the feed. It will turn green with a checkmark and then to save those settings, just click the "remember" button so your feed will stay that way the next time you return to the page.