Don't worry. YOU WILL BE JUST AS COMPETENT WITH THE SECOND CHILD AS THE FIRST! Trust God because things all have a way of working themselves out. I know myself when I'm with my parents (I actually lived with my grandmother and a baby for a year) you can feel stressed out thinking of all of the things you could be doing for them, for yourself. Let people help you, don't try to overdo. You are VERY fortunate to have such supportive parents.
Relax and try to tell yourself - God is merciful and loves mankind and he will NOT abandon you - especially with two babies. You didn't say how long your husband will be deployed out. In fact, we lived in Jacksonville, Arkansas where my son was born (in 1983 - 1985) (my ex & I were in the military - I know how stressful that can be) Do you guys have a place of your own or do YOU need to find one? If you need to find a place, it's probably a bad idea to do this until your husband gets back. I did a move from California to Arkansas in the military - THEY WOULD NOT SEND MY HUSBAND BACK TO HELP!! It was too much - VERY stressful - and I didn't even have children at the time. Probably the worry about your husband is taking its toll as well on your nerves. God protect him wherever he is.
God bless you and your two precious ones. "Look at the birds of the fields, they neither sew nor spin, yet God takes care of these. How much more are you worth than the birds." God says "do not be anxious for anything!" Let him take care of your worries and anxieties. Pray and "cast your cares" as best as you can, bit by bit. Read the 23rd Psalm, find things to do that calm you down.