Okay, deep breaths my love.
I'll give you my background because reading your post actually gave me chills.
19 years old, 400 miles away from family having just started university, was coming to the end of freshers week having had a bottle of vodka glued to one hand and 20 Lambert and Butler permanently glued to the other when BOOM, good ol' reliable AF was late. So I did a test and fell, rather graciously, off the toilet seat having read the positive result.
There is nothing that can prepare you for the shock. All you can do is take big deep breaths and try and figure out what you want to do. It's not an easy choice and it is certainly one you need to seriously consider.
My story now? I have an amazing seven year old daughter who I love with every fibre of my being. I finished up my first year at uni to get the credit, moved back home for support and the rest as they say, is history. It's been hard. Really fucking hard. I had weeks a few years back where I had no money, no electric, no heating and sometimes no bloody hope. I was stuck on benefits in an area where jobs were pretty scarce even before the sodding recession hit. But I always had dd, and I swear to God that kid has pulled me through some really, really crappy times. Becoming a mother toughened me up - I have a fight in me that was never there before, because you have to fight for them. You're all they have and it's all on you.
Things have been pretty amazing for the past...going on three years now. It took some doing but I managed to get myself sorted out and starting back at work was a lifeline. I've had ups and downs and I've been ecstatically happy and utterly depressed. Life, unfortunately, doesn't stop for anybody's blues. You pick yourself up, dust yourself off and wait for the shower of shit to start all over again.
With regards to the choice you're faced with - that's all on you to decide. You're going to wobble no matter what you do sweetheart. I am very much pro-choice, but aborting was never a decision I felt personally comfortable making. I just couldn't have done it. Of course, choosing to keep a baby isn't exactly a walk in the park. But that's the tragedy of being human - sometimes, you have to pick what you feel is the less rocky path, despite the fact both paths have just been completely torn up by one fucker of an earthquake.
A few things that stood out to me:
You've been stupid? Most of the population have been 'stupid' at some point. It's done, it's happened, don't beat yourself up. Give yourself a shake and get your head on straight. And don't you dare let anybody make you feel bad. You're young, you're scared and you don't need the stress.
You can't give the little one the comfortable life they deserve? Bullshit. Kids needs love, stability, a roof over their heads, clothes on their backs and food in their tummies. Anything over and above that simply stems from fantastic advertising. You might not be able to afford to send them to private school or take them on luxurious holidays or buy them a rainbow coloured unicorn, but hey, a lot of people can't afford those things either. Shit happens.
With regards to cost - yep, kids cost a fortune. Mine's just set me back over £100 to kit her out for starting back school in August and that was shopping carefully whilst loaded down with discount vouchers. However...things don't have to cost as much as you may think. Check out sites such as Freecylce and Gumtree and any local Facebook selling pages for cheap alternatives to furnish a house/prepare for a baby - if that's the route you decide to go down.
Where's the father in all this? Have you told him and if so, what did he say?