In the oxygen sheet, insert a new column A and put this formula in A2:

=IF(H2="","-",H2&"_"&COUNTIF(H$2:H2,H2))

I've assumed that it is the dates in column H that you would wish to report on. Copy that down to beyond the bottom of your data, so you can cope with future expansion of the data (e.g. to row 1000).

Then make a copy of the Calendar sheet - an easy way is to CTRL-drag the sheet tab, then rename this to Calendar_O2, for example. Then highlight columns B to H in the Calendar_O2 sheet and do CTRL_H (Find & Replace):

Find what: pap
Replace with: oxygen
Click Replace All

then the Calendar_O2 sheet will be looking at the dates and names in the oxygen sheet.

Hope this helps.

Pete