If so, then run, don’t walk, to these posts by Father Z:

“I haven’t been to Confession for 10 years! I don’t know what to do!”

We do not know the day or the hour

How to confess well? I worry I am not doing a good enough job of it.

And of course:

Fr. Z’s 20 Tips for Making a Good Confession

And here’s one by Father Powell:

Making a good Lenten confession