I have too been struggling with assurance for the past 6 months. Here are some books that have helped (and still are helping) me: (in the order of helpfulness)

1. Assurance by A.W. Pink (Brilliant!)
2. Come and Welcome to Jesus Christ (Good to make sure you are not falling into unbelief in your quest for Assurance, but not directly on Assurance. My favorite book of all time save the Bible)
3. Heaven on Earth by Thomas Brooks (Great!)

The first two are available on the net but the last only has quotes on the net. If you only read one, read A.W. Pink’s Assurance (you can get it at www.spurgeongems.org)- it contains (in a shorter form) most of Brooks’ material anyway.

May God bless through the reading of these. I know what it's like to lack assurance, so I'm cheering you on!
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