Zyrtec D contains an “anti histamine” which reduces running nose, itchiness and allergies. It also contains a “decongestant” which will reduce the block nose.
Yes it probably will help with some of your symptoms.
The “usual steroid nasal spray” is meant for long term use, so I’m not surprised if it doesn’t work in 2 days, perhaps you can try a month of usage.
If you are not better, you might need to see your doctor to check if it is other more serious problems. Take care!