I would recommend a TL071, but not on a 5V supply. Look for a JFET op-amp.

 

It's overbiassed. The transistor is fully switched on and the drain voltage is as low as it possibly can be.
You need to add resistance between the source and ground. That will make the gate voltage lower than the source voltage, which will start to turn off the JFET.
Try 1k to start with, and see if you can get the drain voltage reasonably close to mid-supply.
When you have done that connect a big capacitor across the resistor (say 100uF)

i've used a 5k and got the voltage to 2.7 volts and added a 220uF cap, the result is wonderful, i adjusted the feedback potentiometer to get rid of the noise and got a respectable, almost clear output signal

however, i noticed that all of this was while i was holding the capsule with my hand, as soon as i let go, a very strong humming appeared, im guessing its a grounding issue (even though the capsule is already connected to ground), any ideas?

 

i've used a 5k and got the voltage to 2.7 volts and added a 220uF cap, the result is wonderful, i adjusted the feedback potentiometer to get rid of the noise and got a respectable, almost clear output signal

however, i noticed that all of this was while i was holding the capsule with my hand, as soon as i let go, a very strong humming appeared, im guessing its a grounding issue (even though the capsule is already connected to ground), any ideas?

Is your 0V really connected to earth?
Is the case of the mic really connected to the 0V of the circuit?
When you put the microphone in its case, and earth the case, does it go away?

You might like to experiment with different values of R2, and different JFETs, try 2SK3557, or Texas's new JFE150.
You are operating it at a drain current of 250uA, but JFETs tend to achieve their best noise performance at higher currents, at least 1mA.

 

741 and 748 opamps are too old with awful old specs for good audio.
A 5V supply is too low for a low distortion preamp with a fairly loud output.
I have used many TL071 and OPA134 single audio opamps powered from a 9V battery. Duals and quads are also available.

All audio products use a shielded output cable (from your mic, its ground wire encloses the signal wire so that the signal wire is not an antenna for interference and hum pickup).