Imperfect contrition (servile fear) is sufficient for the forgiveness of sins during confession. A purely servile fear is not though.
*A purely servile fear of God is not sufficient for imperfect contrition. That is one which makes a person avoid sin only because of punishment: so that, if there were no punishment, he would not be sorry, but ready and resolved to sin, regardless of the laws of God. To receive the sacrament of Penance worthily, purely servile fear would not be sufficient.—Bishop Louis LaRavoire Morrow *
However, purely servile fear, with no love of God but only self-love that fears the divine punishments, is at least in theory, inconsistent with the true love of God—Fr. Hardon
Only that desire for remuneration (amor mercenarius) is reprehensible which would content itself with an eternal happiness without God, and that “doubly servile fear” (timor serviliter servilis) is alone immoral which proceeds from a mere dread of punishment without at the same time fearing God.—Catholic Encyclopedia
I’m having a hard time distinguish imperfect contrition from a purely servile fear. I’m questioning if I have “no love of God” or if I do have some love of God. I am unsure and it scares me. I seriously ask myself “Would I have went to confession and stopped doing this sin if it didn’t lead to eternal damnation?”…I honestly can’t really say ‘No’ to that question. I would like to think I wouldn’t, but I’m not sure. I’ve maybe tricked my mind to thinking I would, but like I said, I don’t know how I would react in that situation…so I’m worried I don’t have sufficient repentance for my sins, even with imperfect contrition…
And there are also times where I get anxious and begin to have serious doubts about the faith being true, and the only thing keeping me from committing a mortal sin is the fear of hell, “Just in case”, the faith is true.