15 month old sleep.. some advice please?

My son will be 15mo in a few days, he started off as a terrible sleeper but from about 6-7 months was really good (minus a few bumpy nights here and there).. til about a month and a half ago. We went on holiday and he was in a travel cot by my bed and he slept absolutely fine there (as he always did prior to us going away).. when we came back I put him back in his bedroom and expected a few nights of bad sleep while he got used to his own space again but it lasted 2 weeks before we had to go away again and he was back I'm my room in a travel cot. As soon as he was in my room he was sleeping soundly, not waking up at all through the night.. we got back over 2 weeks ago and it has since been terrible sleep.. some nights even waking up every hour. He wakes up screaming and is hard to settle.. last night we resulted to bringing him into our bed which is something we have never done and it's pretty safe to say we probably won't repeat as that wasn't very comfortable for anyone. I'm just wondering if anyone has experienced the same and how long the adjustment period was with your LO whilst they got used to their own space again? I'm knackered to say the least.. any advice would be appreciated 🥺