Yes, If Box 12 does not indicate a "J", the W-2 income is taxable. If you personally had paid all of the premiums for the insurance it would not have been taxable.
$100 may or may not be enough to cover the taxes on $7,600. If you had no other income, you would not have had a tax. If you had substantially more income, you may owe additional tax.
If you are still on disability, I suggest you contact the provider and increase the withholding.