By Bret Kenwell The S&P; 500 has fallen for seven straight weeks. Here’s why you don’t want to panic now. It has been a rough ride for investors. In fact, the S&P 500 has declined every week for almost two months straight, and the other indices haven’t fared much better. The Nasdaq is also down in seven straight weeks, while the Dow is down for eight. It’s not very often we get a stretch this bad. There tend to be opportunities to sell into a rally. We got one in mid-March, but it’s been all downhill since then. At this writing, the S&P 500 is up 2.4% on the week, but I’m not sure many investo…