Larry, I don't know what to tell you at this point. I inspected a lot of concrete in my early years for Tx, DOT, (Bridges, etc), and did prep work for Contractors on the same type projects and one thing that always seemed to be the "Most Determining Factors" in eliminating cracking was Proper Compaction, and adequate Steel. (Note; this assumes the right "slump" concrete is used, drier being stronger and less crack prone)
Since my contractor was so slow getting anything done on my shop, it was a plus for my slab, since it sat for 3 1/2 months after it was ready, before the pour was actually made, and was rained on a few times but completely dry when the pour was made. This "Set Time" allowed all the "Base" dirt to resettle and compact with no hard and soft spots during that time. I personally added rebar tied to their 6" steel mesh every two feet in both directions across the slab, giving 2' squares between the rebar. I also monitored and directed the vibration of the pour which was a 5" thick slab (plus the footings). I was told about two months later that of the 11 projects those folks poured in a 3 week period, that mine was the ONLY one that did not have even one crack in it and all the others were cracked pretty badly. It has been over 3 years now, and there has been only one 8" long hairline surface crack develop close one end of my DC/Electrical trench that angles over to the edge of the slab. We also used the fiberglass fibers mixed in the concrete for the pour, (which was a first for me, and I don't know if it had any effect or not).
Note: There is not One Expansion Joint anywhere in the slab. The shed room slab was poured later, and there is no cracks anyplace where the two slabs join, or anywhere in that slab either. I also have conduit, water, and sewer lines coming up through the slab in 4 different locations in the building, and no cracks have developed around any of those.
I sure hope yours settles down and the cracks don't open up any further. (I hate Concrete Cracks).