How to regain hope im God Mercy

[Botak]

In the past, I am able to say "I have good opinion on God, that He will save me in the hereafter, and He is always watching and care about me" with confidence.

Then I realized that a lot of time, I use the "His Mercy" excuse to sin.

I also started to found more and more, that I have always been the one at fault, and I have been digging my own hole. God is helping me, but I do not. How can I expect Him to forgive me? Or say with full certainty that He will save me in the hereafter?

 

Also, in the past I thought that if your dua isnt granted it means :

A. God had given it to you, but you dont realize it.

B. God will give you something much better.

C. God is withholding it because its bad for you.

D. God like hearing your dua, and God liking you is a good thing.

However my optimism wane when I realize there are the fifth possibility which is,

E. God does not like you and does not hear your prayer due to your sins

Which, after seeing the amount of sins, and how lax i have become. My perception started to shift toward E.

I know that despairing in His Mercy is a huge sin, but my heart keep worrying, and my mind is fearful that Shaytan will use this to lure me back again.

 I dont want to despair in Him because its a huge sin, and i dont want to go to hell. Yet I am worried Shaytan, or me, will use this to excuse sins. And then God not hearing my dua or plead.

How do I regain my belief in His Mercy?

[AbdusSibtayn]

Well, despair of God's mercy is in itself a major sin. 

The key is to strike a balance- make efforts to kick sinful habits knowing that He's watching and can punish us anytime, and being hopeful that He'll forgive us if we slip. 

Remember that sincerity is a necessary condition for the acceptance of repentance; if someone is not sincere and takes His mercy in jest, then his repentance is not accepted. 

We have traditions I believe which say that sins are a reason why our prayers are blocked and our duas are delayed fulfilment. But take it positively- Allah wants you to kick the sinful habit so that you get closer to Him, and the barriers blocking your prayers are removed. 

What helps me is reading the chapter on 'tawbah' from Shaheed Dastghaib Shirazi's book 'Major Sins'. It always reinforces my hope in Allah's mercy.