I think it's really important to share how you are feeling with your counsellor, especially the part where you're worried that opening the door on your abuse will effect you being able to function.
No one knows you better than you. If this is likely to happen then your counsellor might need to ease up a bit and focus on other things. Your counsellor needs to know if things are getting worse and if it is s/he should back up for a bit and support you in the way that you need.
Children cannot consent to any sexual activity. Our brain's are not fully developed even until the mid-20s. Children, regardless of how smart, do not have the cognitive understanding to consent.
It's ok if you struggle to use the word abuse. People may not like you not being able to view it that way out of care, because they care about you.
If it is getting too much for you then maybe it's time to forget it for a while and concentrate on other things. What do you like doing?