I'd stop taking the microlut. I remember feeling pretty ordinary on mini pills and just had to stop taking them. I had been ok on full pills prior.
The fact that you are not BF that often over night, you will have a very high change of becoming UTD if you don't take any other precautions.
I remember when on the mini pill AF returned pretty regularly even though I was BF.
I currently have the Mirena in which is finally good, although my OB made sure we were not wanting to have anymore before having this put in.