There are so many possible factors (sleep quality, how well work is going, any kind of life-altering change, caffeine intake, alcohol, etc. etc.). It’s very likely in your head, as you say.
I have this theory that taking up PE can be very mind-altering - and sometimes negatively - for a certain percentage of men. Read posts here any day of life and you find guys asking questions that would never have occured to them before they started PE. They become highly penis-obsessed. :) “Help! I have this bump on my shaft!” “Oh, God, I cum too fast now,” or, “I cum too slow.” “Help! I don’t get a hard-on in 31 seconds anymore!” “There’s this vein on one of my balls! Help!”
Before PE we didn’t think so much about our cocks or our erectile response. We had normal lives. We had sex with success. Suddenly we’re measuring them, and checking them out, many times a day, and pulling on them and pumping them and tying them off and all sorts of other new stuff. Suddenly we worry that we are making an impression in the locker room. Suddenly we wonder if the secretaries at work are checking our bulges out and we worry if they are (Is it too big for the work situation??) and if they don’t seem to be checking us out, Is it too small? “Normal” takes on new meaning with all this PE shit.
Questions:
How long has it been since you took your wife out on a date? A real date. Just the two of you.
When you go to bed together, how long has it been since you _really_ played with each other’s bodies before you try to slide it in? And told each other what feels especially good, and taught each other what turns you both on?
You’ll be fine. You just have to readjust some thinking. PE isn’t sex. PE is for the future. Sex is now.