Advice Needed : 5D4N - which pass i need ?

Hello tay.tiffany! I'd say you should consider a 3 day Swiss Flexi Pass, using free travel days for day 1, day 4 and day 5. Discounts will be available for your trips on day 2 and 3.

Just a note on your travel schedule: do you plan to end day 3 in Lucerne or Interlaken? If so, you can't really take the Glacier Express to Zermatt (that is, not the entire route that starts at St. Moritz), as that's a very different route than Lucerne/Interlaken-Zermatt. You can do part of the trip up to Interlaken by Golden Pass though. Then head on to Spiez and take the Lötschberg RegioExpress via Kandersteg and Goppenstein. This route will be a fantastic scenic experience too. You can plan it using the timetable, entering the right 'via' stations.