Phone screen response time after initial rush

Just finished a phone screen with FB two days ago. Before that they asked me what my timeline was like, so I told them I have another onsite coming soon, and they did seem like they wanted to expedite (scheduled the phone screen the same day).

Now its been just over two days and I havent heard anything. Any reason to be concerned? I thought it went well (fit check) but now I’m a tad anxious, especially hearing nothing after how quickly they moved at first. Interviewer said we could talk more at the end of the first call and that they would try to schedule a follow up call, so I am a bit optimistic at least, but I do want them to catch up.