What the status of each home you sold?  Primary in 2017 and second home in 2018?  Primary home in 2017 and primary home in 2018?  Was either home used as a rental or in a business when it was sold?

Unfortunately, you do not meet the look-back requirement as stated below from IRS Publication 523. You can only take the exclusion once in a 2-year period.

Determine whether you meet the look-back requirement. 

If you didn't sell another home during the 2-year period before the date of sale (or, if you did sell another home during this period, but didn't take an exclusion of the gain earned from it), you meet the look-back requirement. You may take the exclusion only once during a 2-year period.

https://www.irs.gov/publications/p523#en_US_2018_publink10008998