So your using the FTB client ? if so, then click on the FTB launcher. Then when it has lauched click on the mods tab. Then click on "Edit mod pack" This will open a new box called "Mod pack editor"
Here you will see all the mods that installed. In your case you wish to know if you have forge mod loader installed. So click on the Jar mods tab. There you should see mine craft forge.
Go check now that it is there.
Edit Please not that FTB is experiencing a few problems with Creeperhost. Thus you need to take into account as it will impact on your ability to play on server.
As an alternative you could in the mean time download a copy of MultiMC. I now carries the ability to use an instance from FTB this will get you on servers with your pals, if configured correctly.
Hope this helps. TFB are working to sort the problem out.