The child youth nurse I saw with dd suggested swaddling in a cot sheet. Because the sheet goes round multiple times they can't get their arms out. I found that was fantastic.

How has the Zantac gone? Improved at all? Have you tried infants friend? My dd was always calmer with infants friend.

My SIL had terrible sleepers and she have me the book Silent Nights. I didn't follow it per say but i did find some great pointers.

Just another thought, how was the birth? Was it traumatic, unusual? Maybe you both feel stressed from that?