I'm desperate at this point...

Hey ya'll! My hubby and I have been married for 4 years and have a beautiful 2 1/2 year old girl. We've been TTC for almost 18 months. Almost 1 1/2 ago I conceived 3 times in 5 months, but unfortunately lost them all before even realizing I was pregnant (miscarriage and the last was tubal). That means up until the tubal I was able to concieve. We conceived our daughter in ONE cycle!?! This is VERY frustrating! Does anyone have any input?-->ALSO today, I'm 4 days late. That's very unusual for me! I'm tired, I'm having sharp headaches on when I stand, food advertions (LIKE CRAZY), peeing ALLLL the time, I mean if there's a symptom I've got it. With my daughter I had every symptom under the sun, so this make me wonder...could I be pregnant? I want to take a HPT, but I hate to set myself up if AF is just waiting to set me up! =( Lots going on my way and I need some help! Good luck lovely ladies!