Blowjobs and sex

I have lost my sex drive and it's hard for me to get into giving a blowjob to my fiance of 5 years. I don't know feels like there is something wrong I am on a mirena contraceptive and we also have 4 year old son that is autistic and a set of twin boys that are 2 years old and recommendations on how to get my libido back or my drive back ? And also to be able to give him a good blowjob sorry to be veage