Prompt 48: The "Why Won't Baby Sleep?" Decoder

My baby is [AGE] and [SLEEP ISSUE — e.g., "wakes every 45 min" / "only sleeps on me" / "won't nap longer than 20 min" / "fights sleep for hours" / "sleeps great during the day, awful at night" / "regressed after sleeping well"].

I need actual answers, not 'sleep when baby sleeps.'

My situation:
- Baby age: [E.G., "2 weeks" / "6 weeks" / "10 weeks" / "3 months"]
- Total daily sleep: [E.G., "I have no idea" / "12 hours" / "9 hours" / "seems low"]
- Wake windows: [E.G., "I don't track" / "I try for 1-2 hrs"]
- Sleep environment: [E.G., "dark room with white noise" / "we live in a bright apartment" / "we co-sleep" / "crib in our room"]
- Feeding pattern: [E.G., "every 2-3 hrs" / "cluster feeding in evening" / "mostly formula" / "I think hunger is waking them"]
- My exhaustion level: [E.G., "I can function" / "I'm a danger to myself" / "I cry when I think about bedtime"]
- Sleep training thoughts: [E.G., "too young" / "want to" / "partner disagrees" / "what even is it at this age"]

Please give me:
1. The 4th trimester reality (newborns aren't supposed to 'sleep through the night')
2. What's biologically normal at [AGE] (wake windows, total sleep, feed-to-sleep association is biological)
3. The 5 most common reasons babies this age fight sleep (and how to address each)
4. The 'drowsy but awake' myth (and what to do instead)
5. Safe soothing techniques that don't require sleep training
6. When to involve the pediatrician (not sleeping at all, weight issues, painful gas, etc.)
7. The 4-month sleep regression (preview + how to handle)
8. The "I'm going to lose my mind" 24-hr survival plan (take shifts, ask for help, lower the bar)

Important: I want facts, not the latest sleep training technique.