How to tell your fiancé you're pregnant when it wasn't quite planned?

My fiancé and I have a 19 month old boy,no have a almost 5 year old boy from my last marriage, we had a pregnancy scare about a month ago and it got us talking about if we wanted another or if we were ready. I started putting serious thought into and figured I'd rather wait until after summer I've been pregnant threw summer it's not fun and I've had a baby right before summer it's a lot easier. With the pregnancy scare I went to switch bc and found out my mirena had come out at some point so I have a prescription for the pill but I have to wait until my period comes, which should be Saturday 3/21/15 the past few days my back has started to hurt my boobs more sore and sensitive craving foods... I just felt pregnant... So this morning I took a test knowing it was most likely too soon to tell and there is an extremely faint line.