I need help

For 3 months, I have been out of it. I don’t feel real, my surroundings don’t feel real. I’m basically bed bound. I go into a store and nothing seems like it’s real. I hang out with a friend and all I can think is “how are you a real person??” I can’t shake it. I can’t do anything. A neurologist put me on lexapro for it, it’s been 10 days on it and no change. Any advice? Tips? I’m hopeless