Lantus acts by forming microcrystals that deposit in fat cells. They gradually dissolve which is what both gives Lantus it's duration and forms the insulin depot. If you are administering fluids in the same area as where you're shooting, it could have an effect on the insulin. I never separated the insulin shot from fluids by several hours. I did not shoot in exactly the same place as where I gave fluids.
Also, keep in mind that fluids can drop the BG numbers. You are "diluting" the amount of glucose in the blood stream. You may want to make sure to test so you have some sense of how the fluids are affecting numbers.
And no, you were not a "loser" by skipping the PM shot. You don't have enough data yet to shoot low numbers. You might want to start posting over on the
Lantus board. There are lots of members who are juggling fluids, CKD, and FD on that board.