Solo is not a huge sin…

I agree with the commenter that the answer to your question is between you and the Lord. I came across an interesting comment on another LDS site about sexuality that seems to address your very issue:

“In my experience and in talking to several church authorities in varying levels, the problem isn’t in the act (of masturbation), it is in the addiction to said act. However the same problem could arise in the addiction of married sexual relations.
When I was a sister missionary, I confessed to my Mission President of masturbating on occasion. He told me that I should keep my thoughts as clean as possible but that it wasn’t a big deal. I was told to keep taking the sacrament.
Later in life my marriage had just come to an abrupt end when my husband walked out. I talked to my bishop about masturbation specifically and his only counsel was that excessive masturbation could lead to problems. I asked him if I should throw away my toys collected during marriage, and he said that it was up to me, and that the church did not have a stance on that issue.
I asked my new stake president the same question after moving to a new area. (I had decided to keep my toys) He agreed and told me that it was up to me, the church did not have hardened fast rule on the subject. He signed my temple recommend.
In my experience, solo is not a HUGE SIN by any stretch of the imagination.”