It can change your hormones but so can other things and there are various causes of feeling moody.
The pill is a possible cause. I know people who have reacted badly to the implant but it was a more immediate thing.
Coming off the pill could change your hormones just as going on it does, whether it is for the better or not is hard to say unless you've been there.
I'd recommend discussing your problems with your GP and coming up with a plan together with them and getting booked in for your smear at the same time.
If you don't get much help from your GP them a local well woman or family planning clinic may be an idea.