JazzieJeff - You are not alone!!!!
I have exactly the same problem with DD who is now 17 weeks, we call it the "witching hour" and it begins at 4pm on the button!
She has been like this since she was about 10 weeks and I have tried everything - nothing seems to have stopped it but she does seem to be growing out of it, very slowly.
We always used to just battle through until about 4.45 when we bathed her (completly different baby) and then as soon as we were dressing her she started again, stopped as soon as the bottle was in her mouth and then completley zonked out by 5!
A few weeks ago, she started falling asleep at about 3.45 and sleeping right through till I woke her at 4.45 for bath as usual and then straight back to sleep again, still fussed as usual after her bath though.
(I think we may have been overstimulating her in an attempt to distract her until 4.45 when she was actually tired the whole time, no signs though, just screaming
)
I tried taking her out in the car at 4 which sometimes distracted her and also offering her some milk before her bath with the rest of her feed after which made her a bit calmer on some nights.
I'm convinced it's a combination of tiredness and hunger, I think she is basically so tired and hungry she doesn't know what she wants and is so upset she wont settle, the one good thing is though that is soon as she has had that last feed she is straight to sleep.
One thing I did find that helped though is a dummy. When she was screaming and we couldn't calm her and she wouldn't eat, sucking the dummy seemed to relax her alot and as soon as she started nodding off, I slipped the bottle in.
The past week, we have actually made it till 5.30 with no crying, she was bathed and dressed and as soon as she started fussing, she just wanted her feed. This came totally out of the blue and hopefully will continue.
The only problem is, with going to bed at 5pm, although she is brilliant and sleeps right through, we are now ready for the day at 4.30am
. I'm not even going to attempt to keep her up later as she seems to be slightly calmer at this time of day now.
I hope your DS settles soon, it's really hard to be dreading the clock ticking down everyday but hopefully, it will get batter.