How can I overcome the fear that the future may bring unexpected problems in my spiriutal life?

I have a question its my inner struggle,I was brought up in an atmosphere where the family had to face lot and lots of small small problems by all means , so my mind got trained nicely how to face the problems how to keep away and do our own things ,my studies really helped to engage my mind .By a devotee’s mercy we came into kc and its a best thing happened in my life and taking up k.c was very easy for me, my mind thinks in so negatiev way, if things go on smoothly i used to think whether anything wrong is happening ,so when Iam with some problems Iam o.k my devotional service is so intense, if things go smooth I have an underlying fear if something bad happens how I will have to face that,I can be absorbed in krishna nicely …… so my mind constantly keeps thinking of how to handle the problems on and on….. without any problem at present and so tackle this Iam trying hard pray to krishna, I  utilize my time in the best way possible in K.C activities  and again the problem  comes when I see myself growing in k.c, my heart is slowly getting transformed nicely, I get a fear what if I keep on going further, I will not take care of kids nicely etc… all sorts of fears crops up…..I try hardly that I should not get time to think try to memorize slokas etc….But mind is a real torture to me all due to my bad karma…

Recently by krishna’s mercy only I got the clear picture what’s the exact problem Iam facing internally, even though externally everything appears good and thought of asking. somebody ..since we are moving from place to place due to my prabhuji’s work, we don’t have a fixed spiritual mentor,I feel its a  silly question to ask and disturb our spiritual master.