Summing Across Unknown Range In Unknown Cell

I've been working on a spreadsheet and these forums have been a great help. I'm now at the very last section and, surprise surprise, it's also the hardest!

I'm creating a stock trade recording sheet. I have a userform ask the user to enter a date, a time, the number of stock purchased, and the price of the stock. These are then entered in a new row.

Now what I want to do is have summary cells which say how many stocks were purchased and the total profit made for each day. Since each time is given its own row, I can't know in advance which rows to sum over. I also don't know on which days a trade was made. So a summary cell should only exist if a trade was made that day.

Could I do something like.... check if the date matches then sum over all the values for that date? So if column A has the dates, can I say "Search which rows in column A have this date" then "for those rows, sum column C"?

Also, how would I create a a row for each traded date's summary cell and enter the date in it? I've attached a spreadsheets which manually demonstrates what I want to do (no macros) and a spreadsheet with what I have so far (basic macros).

Any and all help much appreciated, I just need to get my head around creating and dealing with variable ranges. Is that a really advanced task? I don't think this is a one line solution so please bear with me while I make mistakes!