Worried About Ectopic Pregnancy

I really need someone's help. My name's cassie and i'm 15. I think I am almost 6 weeks pregnant...But I think it's an ectopic pregnancy.I feel absolutely horrible ,and i'm going insane trying to think of what to do.

Okay ,i'm just going to start from the begining.
If i'm pregnant then I concived on october 30th.We used protection ,so I didn't think anything of it.After that ,over the month of november , i've drank alcohol (smirnoff twisted and bud light if that's of any importance) ,smoked weed (3 days in a row if that matters) and cigarettes(close to half a pack a day) ,and (i don't know if im being obsessivly paranoid here) went on those rides the flip you upside down and spin you in circles.

I swear I had no clue I might be pregnant until two weeks ago when I missed my period.And i've only smoked 2 cigarettes since then.I know I shouldn't have smoked at all the second I missed my period ,but it was hard.

Okay ,well after I missed my period ,i decided to wait a week to see if it was just late. But I started having these sharp ,unbearable shooting pains on the left side of my stomach about 6 inches below my breast.At first I thought nothing of it ,but it continued.
So I started checking around and I read the severe pain like that is a sign of an ectopic pregnancy. That really scared me because my mom had a history of ectopics and miscarriages before I was born. (are ectopics hereditery?)

but the thing is ,this past monday and tuesday ,i took two pregnancy tests ,and both came out negative.

So ,if anyone has any idea what's going on ,or if anyone has experienced anything similar , please please let me know.

Would it be safe for me to wait another week before I go to the doctors?Because maybe my period is just late ,and I really don't want to upset my dad and have to go to the doctors if there's nothing to worry about.

And , is there even the slightest chance that maybe it's not an eptopic pregnancy? Is it possible that I might be pregnant but everything is fine? Like , maybe my hcg levels are still to low to detect?

I'm sorry this is so long , but i'm just so worried and so scared , anyone who has any kind of information ,please e-mail me.