ok ladies help!!

So I'm on my 3rd pregnancy. I have twins that are 7 and a six year old. I'm currently 25 weeks pregnant. I took a nap yesterday with my husband and when I woke up my heart was beating so fast you could see it on the outside of my shirt! I was having trouble breathing. I thought I was have a heartattack. I got my husband to feel my chest and he immediately grab me and held me and after about 5 mins it started to slow down. I'm still have shortness of breath. I'm only 22. I have no idea what is wrong. Should I be considered? Does anyone have something similar or know what's going on with me