I had a similar issue, turned out I wasn't sleeping enough. Here is an easy way to fix it.
You're likely more sedentary, or not going to bed early enough to deal with when you wake up.
This is a common thing for people to start doing once they start working. Here is how you get back to sleeping normal amounts:
Stop drinking all caffeine by 17 hours before you need to awake the next day to get to work in time (so if you have to wake up at 7 to get to work, stop drinking it by 2pm; you may think it doesn't keep you up, which may be true, however it does make you sleep less deeply). Try dimming your entire house/apartment 11 hours before you need to leave for work, turning off all screens, read, listen to soft music, etc for that hour before bed. No watching TV or doing anything other than sex and sleep in bed.
Then go to bed 10 hours before you need to leave for work, have a real bedtime.
Do this for about 2 weeks, and you'll find you are so mentally alert. You'll feel like your old self in no time.
If you're trying to make sure you're sleepy enough to fall asleep 9 hours before you have to go to work, and you look at the half-life of caffeine: 4.9 hours on average (with a huge personal variance).
If you want to be "uncaffinated" when you fall asleep (which is hopefully <=8 hours before you get up, and a good 10 hours before you leave for work), you get less than 2 half-lifes, aka you get to drop your blood caffeine level to only 25% of what you had when you stop drinking it. Remember, caffeine not only causes you to stay awake, it causes your sleep to be less deep than it otherwise would.
Additionally: Effective use of caffeine means never drinking it in the morning (the only thing caffeine helps with in the morning is treating caffeine addiction. It's an antagonist of adenosine receptors, meaning it makes it so this chemical, which doesn't show up in your brain till late in the day, can't make you sleepy).
If you find caffeine helping you at all in the morning, you need to dial back your caffeine usage. It only starts becoming effective near 5-6 hours after waking up, and it's effectiveness skyrockets as the day goes on. So basically it takes less and less to keep you up the longer you stay awake (and has almost no effect to keep you up before a few hours awake, so morning coffee is somewhat silly).
If you are trying to get the adrenaline surge you can get when: 1. Not a caffiene addict, and 2. an occasionaly drinker of strong coffee, just do a few jumping jacks (like 4-9). It will do the same thing to your heart and you'll have caffeine as an effective tool around noontime which can be used to keep you awake the rest of the day at work, yet not interfere with your sleep.
You're likely more sedentary, or not going to bed early enough to deal with when you wake up.
This is a common thing for people to start doing once they start working. Here is how you get back to sleeping normal amounts:
Stop drinking all caffeine by 17 hours before you need to awake the next day to get to work in time (so if you have to wake up at 7 to get to work, stop drinking it by 2pm; you may think it doesn't keep you up, which may be true, however it does make you sleep less deeply). Try dimming your entire house/apartment 11 hours before you need to leave for work, turning off all screens, read, listen to soft music, etc for that hour before bed. No watching TV or doing anything other than sex and sleep in bed.
Then go to bed 10 hours before you need to leave for work, have a real bedtime.
Do this for about 2 weeks, and you'll find you are so mentally alert. You'll feel like your old self in no time.