Why would there be a big difference in my Deductions and Exemptions from 2017 to 2018?

[VolvoGirl]

Yes there was major tax law changes.  The personal exemptions (4,000) are gone.  Now you get a double Standard Deduction.

This year the Standard Deduction will be doubling so many people will be switching to the Standard Deduction.  And there is a max 10,000 limit (5,000 MFS) of property tax and state taxes "SALT".  And you can only deduct Medical that’s over 7.5% of your AGI.  Also the deduction for job expenses have been suspended.

FAQ on 2018 changes https://ttlc.intuit.com/questions/4482394-how-will-tax-reform-affect-my-2018-federal-tax-return

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