Scared to go into maintenance mode

Hi! I'm 5'5' and in the past six months I went lost about twenty pounds, now weighing 128 pounds.
Thanks to a lot of research, the beachbody workout programs and MFP, I am now totally addicted to working out and have a lot of knowledge about nutrition. Still I struggle when it comes to the amount of calories I should be eating.
I keep my daily calories around 1400 most days and my macros in the 40/30/30 ratio and workout for about and hour and a half a day, six days a week pairing CLX and Zumba.

I know I should be eating more (2100 calories a day according to MFP) but even though I really don't to lose anymore weight I am really scared to eat more and gaining back the weight that I lost.

Anyone as any tips or advice?