Creation of 2nd iTunes Library has resulted in all songs in both libraries being duplicated.

Hello everyone. This is my first time on the forum. I admit I can't figure this one out by myself. FYI I am using iTunes vers. 12.13.1.3 on a windows 10 laptop.

For each track there are 2 entries, one is in bold print & the other is gray. As the album plays through the alternate tracks play so each track isn't repeated twice. I checked the file location of the tracks pairs & one comes from C:\ drive & the other comes from the D:\ drive which is where the 2 libraries are located. I haven't lost anything & the library is at least functional but I obviously did something wrong. I'm too concerned about making the situation worse to play around with pathways etc. on my own.

I would appreciate any suggestions as to how to proceed next.