Cancelling wedding to elope etiquette?

FH and I are so stressed out about our wedding. Originally, we were going to get married at the courthouse, but our families berated us until we agreed to have a wedding. FH and I are both still in college and graduating this year, with him starting his masters program right after graduation. The more and more we talk about and plan the wedding, the less that we want to do it. We have a VERY tight budget ($2000), only one of us will be working while he's in grad school, our families keep adding to the guest list, he is too busy to help plan, it's enormously stressful, and we have no interest in a wedding to begin with. Our date is October 29, 2016. Save the dates have already been sent out. How do we go about telling our guests that we've decided to cancel and get married at the courthouse without everyone getting angry with us? Thank you for your help in advance