Displaying totals for current day/week/month (not trailing)?

We’d like to use using Grafana+Prometheus to monitor bandwidth utilized in a given pay period (typically, the current month), but I’m not exactly clear how to write the query that will give me the utilization in the current month, rather than in the trailing 30 days?

The measurements come from node_exporter's node_network_transmit_bytes metrics (a counter of bytes transferred). I can observe the utilization over the trailing 30 days with a query such as:


But how would I write a query for “increase over the current month” (relative to now)? Or over a different time period (say, week, or day)?

I’m rather new to Grafana and PromQL, so I apologize if I’m asking an obvious question. I did try to google for the answer, but wasn’t able to find much.

FYI, this might help https://github.com/danrabinowitz/time-period-prometheus-gateway