Feeling Depressed

so I had a horrible lash out at my son during changing and I'm hurting so much right now for what I said to my 20 month old. I feel so bad that I just want to die. my soul is crushed. I CAN'T take back for my stupidness and selfishness and I feel like I CAN'T give him the best of me that he deserves. I am not the mother I want to be right now. normally we are great together... Lately we're all under the weather, him esp. being sick too... and I may be pregnant as well. I am so down the dumps for my actions with him and hurting. I love my son so much and normally I'm overdoing my affection for him daily except the last couple of days. I am hoping and praying he doesn't remember these weak moments of mine.... I bawled my eyes out and he started crying too. please, any mothers out there need reassurances, thanks..