Also, heavy weather.
Difficult, as in Tom found calculus heavy going, or It's going to be heavy weather for us from here on. The first expression originally referred to a road or path that was hard to negotiate; the variant alludes to bad weather at sea. [Mid-1800s]
make heavy weather of. Make hard work or a fuss over something, especially unnecessarily. For example, They made heavy weather of the differences between their proposals, which actually seemed much alike. This use of weather likens a commotion to a storm. [Mid-1900s]
Examples from the Web for heavy going
Historical Examples of heavy going
The heavy-going eland was soon overtaken, and as it trotted to one side, was passed.The Bush Boys
Captain Mayne Reid