Could it be having an effect on the medications you take?  There really is no reason for this, and if you look at old cookbooks, you see that there was a lot of food made with gelatin.  I only take very small amounts, so I haven't seen that effect.  I had tendonosis in the right shoulder, and that only got resolved after eating more protein AND including daily gelatin supplements (though as I said, in very small amounts).  Also, my fingernails were soft, but now are hard and "snappy" when I clip them.

The strange thing about your experience is that it is tryptophan that can make you drowsy.  I don't know if anyone has ever reported a case like yours.  One possibility is that you are very low in tryptophan, unlike many Westerners.  You don't need to take gelatin as a supplement, depending upon your diet.  I take tiny amounts of some supplements, just trying to make sure that I have enough of the really important ones that I may not be obtaining enough of, so I'd suggest you only take very small amounts - perhaps 1/16 or 1/32 of a teaspoon each day, in the middle of a meal.

It sounds like you may be especially sensitive to the amino acid profiles of the protein you eat, so you might want to try and keep track of what you eat and how it effects you in this context.  Also, if you mean sour cream, the ones I've seen don't have much protein in them, though cottage cheese does.

I make my own jello.  I buy the knox brand plain packets of gelatin and use tart cherry juice.  Tart cherry juice is really sour, so I add 1 1/2 TBS of sugar per packet. Black cherry juice makes good jello, too.   It's a good dessert.  I've been putting whipped cream on top.  You can also blend a few black cherries and some honey nto the whipping cream for the topping.

Several days ago I saw gelatin on a list of foods that contain MSG!  I stopped eating it since then, and I am just starting to feel better today.  Does anyone know anything about gelatin and MSG?