Allergy season weakness and fatigue... suprise

Spring is in full swing and I'm on major antihistamines. Claritin-D for those of you the know. Claritin has an antihistamine (lortadine), but the "D" is pseudoephedrine, which basically a decongestant that constricts the blood flow to your nasal passages so you have less phlegm and runny drippy nose. My allergies started a couple weeks before The Wildflower triathlon, and while there I had a really bad sore throat, and when I got back to Chicago the allergy season was in full swing, suddenly, requiring the addition of the "D" decongestant. The week prior to the race I had been on Antihistamines only, the regular claritin without the "D", but now I need the pseudoephedrine

There is some kind of side effect to all this that makes me basically want to sleep every minute of the day. I'm not sure if it's CFS (chronic fatigue syndrome) or if it's just a side effect of my allergies or a side effect of the drugs in Claritin, but I am so tired every moment that I am not moving that I could, and frequently do, fall asleep sitting in my chair.

I just went for a run, and I don't feel the fatigue on the runs, but a side effect of it is that I really wanted to walk a lot on this run. I did, I walked like 15-20 seconds three or four times on this run today and I still managed to pull down 8.5 minute miles. I don't know how I did it. A sub 3-miler and I started to hit my stride right in the last 3 tenths of a mile as I was catching up to this girl running in front of me.

Typical shit. I don't hit my stride until mile 3, and I seem to have this natural affinity for the 8.5 minute mile pace.

UPDATE: I wanted to updated everyone that I stopped taking the "D" and reverted back to Claritin (Lortadine only), and my fatigue has been basically eliminated. I also think it has to do with getting normal sleep, which has been a problem of mine for a while (I'm a total nightowl) but it seems that the pseudoephedrine was making me quite drowsy.