B737-800
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 10
Situational Awareness; Distraction
Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance
Human Factors
On final with strong northwest winds. Vectored Aircraft X from NW descended to 4000. I was vectoring Aircraft Y from east side to go behind to set up a stagger. When Aircraft X was at 5300 feet and Aircraft Y was at 064 feet. I gave Aircraft X 4000 again; then descended Aircraft Y to 5000. I thought I would have 1000 feet easily with the way aircraft were descending that day. Unfortunately; I had to give Aircraft X a speed reduction which I assume is why he leveled at 5000 and descended very slowly; while Aircraft Y descended quickly. I lost my 3 miles/1000feet. Then Aircraft X did not join the localizer as instructed. Aircraft X read the instruction to join back. I then broke out Aircraft Y and called traffic. I would also like to mention that I got about 5 hours of sleep that night and the night before. The questionnaire asks how many hours I try to get; which is 8. But how much I actually get is usually between 5 and 6.Also; before I took position; the supervisor handed me a paper with a name and number; my bank called about my mortgage. I was trying to figure out how to delay a payment because we had been furloughed and unpaid for 34 days or so; so I was distracted by that a little; because I was worried about what I was going to do since I was unpaid.I misapplied the altitude leaving rule. I didn't visually observe Aircraft X leaving 5000 before I gave Aircraft Y lower. I pressured myself into descending Aircraft Y so he wouldn't be high on the approach; since it was IFR. I should have based Aircraft Y a little later; and held altitude longer to guarantee I could use altitude leaving.
Seattle TRACON Controller reported a loss of separation due to a rule being misapplied as well as possible fatigue and distraction by the government furlough.