I loaded the reel with 100m of monofilament line by attaching the reel to the rod, threading the line back through all of eyes on the 4ft 6in rod and then wound it onto the spool of the reel.

so, is it the way I have gone about doing it?
or, is it that I haven't used enough line by using only 100 yards on a reel that takes 200 yards?
or, is it perhaps the possible poor quality of the monofilament line which I used?
is there a better fishing line than monofilament for spin fishing perhaps?
or, possibly some other reason which I have not listed above?

please help! because I have had to cut short my fishing session on two separate occasions now as a result of the line birds nesting on the reel.