Could I be pregnant?

I have the contraceptive implant, and have done for around three months. The only side affect i really experienced was some light unexpected bleeding. 
my boyfriend and i always use condoms, with 1 exception. however, i have bled since then. 
i keep feeling cramping but without having any blood, and i have felt nauseous more often than usual. i have also had some drops of liquid from my nipples, sometimes clear and sometimes whte. 
i am completely unsure what to think! the first two symptoms are common with the implant, but what about the liquid? it should be way to early if i am pregnant to be lactating, but if im not (fingers crossed) what the hell is happening????