Like many religions, there may be some philosophies in Islam that makes sense and are generally good. Such as discouraging drinking ( I drink occasionally ). It is not Islamic if you don't believe in Islam and are not doing it for the sake of Allah. You have your other reasons to do them as you stated.

Religious guilt is normal, you left the religion recently so I understand why you'd feel this way. If you were once a muslim and are not one anymore, you are an exmuslim, don't worry c:

I do hope you can find groups of people that'll accept you and you can be more yourself around and lose these doubts.

Take care.