Why did my standard Federal deductions go down from 2017 to 2018 when I made more money in 2018?

Actually, the Federal Standard deduction went up (by a lot) from 2017 to 2018.  Do you mean something else, like taxes withheld?  They generally went down under the new tax law.

For 2018 the standard deduction amounts are:
Single 12,000 + 1,600 for 65 and over or blind
HOH 18,000 + 1,600 for 65 and over or blind
Joint 24,000+ 1,300 for each 65 and over or blind
Married filing Separate 12,000 + 1,300 for 65 and over or blind