USA Citizenship FAQ
Physical presence is the total days you were physically inside the US (need 913 for 5y route). Continuous residence is uninterrupted residence — broken by trips of 181+ days (rebuttable) or 365+ days (automatic).
There's a rebuttable presumption that you broke continuous residence. You can try to rebut by showing you kept ties to the US. Consult an attorney.
You broke continuous residence automatically. You must re-establish residence: wait at least 4 years and 1 day (or 2 years 1 day for spouse route) after returning before filing again.
Yes — per USCIS, any day that you are present in the US for any portion is counted as a full day of physical presence.
You need to wait until you accumulate enough. No discretion is available for shortage.