This sounds really bad. Why would you order so many shots?
This would rip up my stomach and probably kill me.

Starbucks is pretty weak. Maybe it's more like 3 regular shots. Do you drink a lot of caffeine regularly? If you do a lot of energy drinks all day, then maybe your body is immune to it.

My gues is all the carbs in the syrups are making you sleepy.

PS. Why would you order an 8 shot latte this late at night??

Sam-I always order 6-8 shots because I like to taste the espresso in my drink with just a little bit of the syrup and if i'm ordering a latte i actually need the caffeine, normally I just get a tea with steamed milk. And when I don't stop at starbucks I just drink water.

Blondie-I thought I was gonna head out with some friends, but ended up just heading home because one of the guys was a pig and wouldn't take his eyes off my boobs

8 shots? Damn girl, as a barista I say you are better off with a regular drip coffee. Get a cafe au lait if you like the steamed milk (I do) but ask for more coffee than milk. Or get a red eye (coffee with a shot or two of espresso).

With that much caffeine you might just be overtired. I find that once I hit a certain high point, my body just goes over the edge and starts to crash.

It's because you always order 6-8 shots. When you drink that much coffee, eventually it doesn't do anything for you anymore.

Cut way down on the coffee and you'll be able to feel the effects of it more. If you must order that many shots, make most of them decaf.

Okay, here's the deal:

First off, as Sam mentioned, the human body quickly develops a tolerance to caffeine. This results in two things: the stimulatory effects of caffeine are greatly reduced, and the user experiences noticeable withdrawal symptoms. In other words, when Mr. Coffee Drinker "wakes up" to a cup of joe in the morning, he is actually bringing his body back to a baseline state from one of withdrawal.

If you have black, green or white tea on a regular basis, you are a caffeine addict. The more you have, the less effective it becomes. If you had some tea or coffee earlier in the day, that may explain your fatigue. Or, you know, you were just tired.

But there's a much more significant problem at the heart of this question...

You frequent Starbucks. Good God, girl, what are you thinking?! Starbucks is to coffee what Popeye Sticks are to cigarettes!