Unplanned, not sure how to feel

I'm going to post anon just because I'm still figuring out my feelings.

I have 3 little girls a 3 yr old, 2 yr old, and 4 month old (she was due Oct 13 2018 but was at 35 weeks in Sept 2018 and had time in the NICU). I have been taking my birth control (Amethia) religiously because I didnt want another baby for another 4 years. Last week I just felt different, and today it really hit me. So even though I didnt have a missed period I said what the hell and test, and it was postive. So now I'm expecting baby number 4.

I haven't told my husband yet as I dont even know how I feel yet. Supportive words would be nice.