Supplementing? Baby pacifying? Mama needs sleep! help

Blair
My almost 7 week is thriving! He is probably about 15 lbs (major chunker!) he has suffered from reflux all this time and it seems the nexium has finally begun to work! But I think I'm being "used"! Lol. I thought it was a growth spurt but now he wants to nurse every 2 hours but only for like 6-8 minutes with an occasional longer feed. It's exhausting. I have a 6 year old who needs mama too and my hisband has had to travel a bit for work. I have no other help. So I decided today to officially start supplementing- atleast at night to see if I can't get us back to a 4 hour schedule. (My daughter slept thru the night by this point) he is not on any sleep or feeding schedule and I feel that since he is obviously gaining weight, I could try to start working toward this goal. 
Does this sound like he is pacifying on me? How did you introduce supplementing? (He has had a few bottles since birth -maybe 10) what formula do you use? I saw there are "supplementing" formulas but have no experience with this. Any advice would be great. I'm so ready to enjoy this baby boy but I've been soooo tired that it's hard to!
Update! 10pm feeding- 4 oz of the similac supplementing. 12:30 he woke up starving (I thought maybe just a dirty diaper but he was just hungry) was losing hope at my attempt for sanity. Gave him 2nd 4oz bottle and he slept then til 5:30!!! Baby steps! I'll take that! I let him nurse at 5:30 and pumped after (pumped 8 oz!!) breast feeding during the day and will try this again tonight.