No, you're not imagining it. The use of that annoying phrase "thoughts and prayers" really has increased exponentially in the last couple of decades, especially in North America. Here's the Google Books chart for American English, 1850-2008:
The British are not so guilty, but they have also increased their use of this cliché
The evidence on the corpus of Contemporary American English for "thoughts and prayers are with" is even more striking (the third column of numbers is occurrences per million words):
Photo by Tom Pumford on Unsplash
1990-1994 | 5 | 104.0 | 0.05 | |
1995-1999 | 6 | 103.4 | 0.06 | |
2000-2004 | 13 | 102.9 | 0.13 | |
2005-2009 | 23 | 102.0 | 0.23 | |
2010-2014 | 20 | 102.9 | 0.19 | |
2015-2017 | 42 | 62.3 | 0.67 |
Photo by Tom Pumford on Unsplash