ANSWER:

You were totally wrong for missing salah again, even if you were sick you should have prayed sitting down, if you couldn’t stand or lying down if you couldn’t even sit! 

There’s no need for renewing the Shahada but you must repent sincerely to Allah, with deep remorse as your iman seems to be weak and you miss prayers at the drop of an hat. Do a lot of extra night prayers and other good deeds like charity etc to try to compensate for missing prayers intentionally. 

 

I made a lot of dua during Ramadan and Umrah asking Allah to forgive me for missing salah my whole life. But while in makkah (after umrah) I became very sick. ‘cuz of this I missed Salah for 3/4 days, and the salah after I became a bit better was on and off. I heard from a scholar that you should do your shahada once again. I did it. Are all my past good deeds erased because of this?