Is it possible that working in an office (for between 3-7 hours at a time) with no natural light at all, and fluorescent tubes that are not designated "full spectrum light" might cause continual depression similar to SAD?
This is a loaded question that needs parsing.
First of all, there is no magic to "full spectrum light". It has no special antidepressant benefits, contrary to the hyping of light bulb and light box companies. It is also electrically inefficient and needlessly expensive.
Second, we do now believe that there is a general light-deprivation factor that can trigger and maintain depression at any time of year; winter is only the most obvious period for the population as a whole.
Third, you need to consider your overall daily exposure to light. For example, if you were to use bright light therapy at home before going into work, your workplace lighting conditions would likely become a secondary matter.
Finally, consider that your depression may result from factors other than light deprivation. Sounds like you should have a clinical consultation.