It sounds like your pet could have one of two problems. He's either suffering from allergies or he has a respiratory or eye infection.
If the gunk from the eyes or nose is clear, you can wait it out and see if it resolves on its own. If it's green or yellow, you need to see the vet right away for antibiotics.
You can also try flushing the eyes with warm saline.
Keep in mind that parasites can also cause eye discharge so you should see the vet for a fecal to rule this out if you have not done so recently.
Let me know if you still have questions.