Stop looking at it if you're going to fret over the drops... hell, crowing over the ups is just about as bad.
Go look at a historical chart that covers decades of investing, and see the upward trend? If you you magnify that line and start looking at all the jaggy little downward and upwards bounces over a year - that is what you are doing - focusing on the wrong part of the chart instead of pulling back and seeing that overall beautiful upward trend. THAT is why you can't scrutinize the day to day stuff. Cause it doesn't matter if you're talking long term investing. Big picture stuff here, and you need to internalize that part.
Like everyone else said, if you're not going to need the money for years and years, what happens day to day (or week, or month) is meaningless. Delete the spreadsheet and stop checking it often, unless you can see that a short term loss is meaningless since technically you should be in it for the long haul, and the only way you are going to lose money is if you panic and sell, thereby locking in the losses.
And for the record, I'm a new investor (new to at least understanding it anyway) over the last year, and I've lost over $20,000 in the last week and I am FINE. It just makes me a little sad I don't have some ready cash to throw in there right now.