Self Doubt?

Is it self doubt or low self esteem? Am not sure… I have a job now and sometimes I feel like am not good enough to be here. But then I draw confidence from the fact that God put me here for a reason. This is probably private. I don’t think anyone gets me though, I can hear my heart pump loudly..literally!! And am scared, I pray I get good at this. I hate feeling irrelevant or useless. It is the worst feeling. But then I should stop complaining, I have been truly blessed (hmmm). And I know my time is coming, good times. Maybe I should stop worrying and take each day as it comes *i write this with a smile on my face * . The Bible says not to worry about what we shall eat or drink for the birds in the sky don’t grow food but are fed by God himself, then how about us children of God? Am not sure where am going or what am supposed to do at this job, but am confident in the God that put me here, he will come through for me !!