Allergies versus Headcold?

I’ve been sick since Thursday night, I think. It feels like a cold, starting with extreme soreness in my soft palate, moving to sinus headaches, runny/stuffy nose, scratchy throat, dry and itchy eyes, occasional sneezing fits. I thought I might have a cold, except the sneezing fits worsened at my friend’s house, who has an overgrown blackberry bush that’s flowering now. I’ve taken Sudafed and Dayquil, which normally help out a lot if I have a cold, but they didn’t have any effect this time. I’m going to try Claritin later just to see if it works, and find that perhaps I’m suffering from late-onset allergies. But I wanted to hear, perhaps from those who have allergies, what the difference in symptoms are between allergies and the common headcold? If I suspect I have allergies, my next destination is the clinic.

cold, sx resolve in about a week,
allergies, persists, unpredictable, try Nyquil for sleep and no other cough/cold meds, only one product at a time esp if combination mixed such as Nyquil.

Common Cold Or Allergies?