1. Should there be a feeling as being a muslim or is believing enough? 2. If dua seems to be anwsed is this always from Allah? 3. Is there such thing as being weak for making a certain dua

Apologies for this answer, but if you suffer from waswas, I really do not want to play into increasing it for you. Therefore, if this is the case, then you should focus on that which is beneficial to you and ignore such thoughts. BarakAllahu feek.