When to test?!

I'm about 6-7 dpo. Af is due in 6 days. I really think I'm pregnant so does my husband. I've been having pains in my stomach and they are worse when I lay down. I have to pee at least once an hour but when I'm laying down its at least 2 or 3 times an hour. I've been getting extra thirsty at work and having terrible headaches. Also been having some nausea. It's driving me crazy not knowing for sure and I'm not trying to get my hopes up! When is the earliest I should be able to test?!