Am a little bit confused by what you mean putting my meter in series? Where else in this set-up could my meter possible be?

Here is a diagram showing what I mean. Just remember your meter actually has 2 different spots to connect your red/positive lead depending on how many amps you expect to read. 1 is rated and fused for 10A and the other (the one you were using) is rated/fused for probably 200-500mA (can't see it clearly on the picture). Don't exceed these limits otherwise you will have to open your meter up and replace blown fuses.

I feel a bit embarrassed by this one but we all gotta start somewhere.

Ya don't sweat it! I see HVAC/Refrigeration techs that are supposed to know this, use their meters everyday and still make that mistake more often than you think. 😉
https://www.electronicshub.org/current-measurement-using-multimeter/
Here is the site where I got the diagram which has plenty of more useful diagrams/explanations for using you meter.