Answers
How can I know I am really saved?
Assurance does not come from remembering a strong feeling on a particular night. It comes from three things you can check today: you trust Christ rather than your own record; you find sin grieves you where it used to please you; and you love people you once had no time for. John wrote a whole letter so that believers could know, not hope, and the Spirit Himself testifies alongside your own spirit.
Go and see for yourself
These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God.
1 John 5:13
The Spirit itself beareth witness with our spirit, that we are the children of God:
Romans 8:16
We know that we have passed from death unto life, because we love the brethren. He that loveth not his brother abideth in death.
1 John 3:14