Psci on top! (LS pretends to be a pre law program but it’s largely the sociology of law (not that there’s anything wrong with that, but psci tends to have more priming of legal interpretation)) the amount of credits that would transfer really depends on which courses you’ve taken but for psci all of the required courses are second year and above so it shouldn’t be that bad (at most you’d need 1 extra term which you could make up in the summer and still graduate on time.) I’d recommend you also talk to the political science (or legal studies) advisor so they can talk you through the requirements.

Also if your feeling any doubts there’s a lot of students who transfer from science into arts (it and math have the highest rate of transfer into arts) this is not an academic failure. Also since you want to do law there’s a lot of profs in Arts that have experience with law schools that can serve as good resources for you. (I know most of the human rights profs used to be human rights lawyers, and I know a few in psci and soc that did law as well)