did you configure with txindex=1?
iguana keeps not only txindex=1 level of information, but a complete block explorer level dataset, which is probably overkill for a home user, but yet it does it
as the utxo dataset exceeds the RAM, then you will need to access the HDD more and more
a full node that is tracking just your wallet's tx vs a full node that tracks tx and balances for all addresses, this changes the memory required by a large factor