I had the same thing! Extremely active baby that just disappeared. I was doing the drink and lay down thing and just felt an occasional swoosh, almost as if only gravity was making the baby move slightly. Of course I was worried, but I also felt my appetite was still large and I was still tired in the same way and I waited it out. Turns out, my husband had been sick and even though I was doing everything I could not to catch it, I did a bit. I was just run down and my midwife reassured me that that was probably why I wasn't hearing from him. She said to massage my belly more to stimulate him if it happened again.
Honestly, trust your instinct on this one. If you still feel pregnant, you probably are. If you are really worried- really feel like there may be something wrong- insist on it and don't let anyone make you feel paranoid.