feeling very overwhelmed in medical school

Juggling revision and clinical placements can be overwhelming, and it might mean you've not been able to study in the same way as you did in your pre-clinical years. I know this is easier said than done but try not to be too down on yourself, you've still got time before your exams - your passmed score is getting there just now and is likely to come up a lot between now and the end of June! Also, comparing yourself to your peers is a sure-fire way to end up feeling like you're failing when you're not!
I would advise you to talk to your personal tutor about how you feel things are going - they can help put things in context for you in terms of what level you're at now and where you need to be for your exams. They might also have some pointers on different revision techniques, or put you in touch with your university academic skills team (or equivalent, different universities will have different job titles!) who can talk about how to balance your revision and put together a plan for your exams.
What other resources are you using aside from passmed and your uni handouts?
In terms of Passmed itself, take the time to read the explanation and the comments (the comments section is not only good banter but also often has useful explanations or helpful mnemonics). If there's anything in the answer that seems particularly important to remember then you can copy it into an excel sheet or anki (or anything else you find useful) for revision later. You might be doing this already though!
Also, have a look at your learning objectives. That's what your exam is going to be assessing you on, so make sure that you know what is and isn't in your objectives (although they'll probably be kept deliberately broad!). Keep in mind that passmed might be asking you things that you aren't going to be examined on yet! Look at what the big topics are in terms of the learning objectives (if in doubt, they tend to be either things that are very common or things that are very life threatening).
Finally, keep an eye out for any revision sessions in the run up to your exams - if your own uni societies don't have anything organised, you might find some advertised on facebook from other universities. They wont teach you everything, but they will normally cover high yield topics.