If any cell in column B contains X, take number from column C in same row and add them up.

Hey folks,
I am putting together a personal expense spreadsheet and need help with this one part.

On one sheet I have all my debits listed, date-category-price. On a second sheet I have the totals for each category for that month. Each month will have its own sheet.
I want to take all the debits from a certain month and combine them with their respective category be shown on the given month's sheet.

I want the equation to automatically filter out any entries outside of the target month so that I will be able to select the column as opposed to selecting the specific cells within the month.
This will make for a more automated and "live updating" system since I wont have to change the selected cells every time I enter a new debit.

I have attached a simple example of what I am looking for.

Thank you so very much for you help, I really appreciate it!!!