Where is the money that was in the economy pre-lockdown?
A very insightful question. The thing I'll add here is the famous identity, MV=PQ. Essentially you're asking why Q dropped (real goods &amp; services), while M (money supply) likely is the same. There are (at least) two answers: 


V (Velocity) could have dropped - which has the same effect as shrinking M. $100 making 10 round trips is very different from $100 making only 1 round trip. 
More nuancedly (sp?) - You could be seeing a collapse in the "composition" of the Money Supply. I.e. Maybe M2 collapsed back into M1, etc. If lots of people called in their loans (M2+) &amp; converted to cash (M0), the same amount of money might be there...but it would have been "sucked" from the system, in a sense.