Don't feel afraid to talk to the surgeon, it's his job to fix you. Ask him what might be going on and what you need to be doing. Also ask him for a realistic timeframe to recover.
That said, 6 weeks is still very soon after what was presumably a big trauma to your knee (how much meniscus was removed?). Your knee needs time to recover (think months not weeks).
The dislocation feeling sounds like perhaps your muscles aren't working right, are you working with a physio? If not, you probably should. Also with menisectomy, the biomechanics in your knee have been permanently altered and your whole body and esspecially your knee need to be trained to get used to the new normal and that takes significant time. Maybe you need to use some sort of light support to help you while you build confidence in the knee. Again, physio best placed to advise.
You also need to get swelling down as that will cause discomfort, elevation, ice, medication if needed. Try
Not sure what you mean by FCL?
There's good info in the meniscus primer in the learning portfolio
Good luck
