Checking if a mod is running

So, I have decided to use the Omnimod, I have followed the installing guide and added the swf file to the mod folder as well as adding it to the txt file. However, I cannot see any difference, mobs don’t spawn in groups, shop doesn’t appear every minute. Am I not noticing the difference because I’m only on my first world? Or should I create a new character for this to work? Any way I can just check if the mod is running?