First I commend you on your attitude towards it all. I agree you are not a stupid girl - but you don't make stupid decisions either. You may have made and undesirable decision, but that doesn't make it stupid.
First, I would find out if you are indeed pregnant or not. There is no sense in telling your parents at this point, but if you are scared to get pregnant you need to be talking to your partner. Protecting yourself against pregnancy is just as much his responsibility as it is yours. If you are both using a means of protection - its only better for you.
Feel free to email me if you need someone to talk to.
If you are indeed pregnant the first person you should be telling is the dad - NOT your friends!! They are not the ones who will be financially and emotionally supporting you and your child for life. Your partner should be with you when you tell your parents and you should be with him when he tells his parents. Its the responsible thing to do. Show both of your parents that you are united in your decision to commit to this pregnancy and this baby.
I admire your maturity and wanting to take responsibility for this baby. That's a huge thing right there.
There's no easy way to tell either the father or your parents. Expect them to be shocked, hurt, disappointed, even angry at first. Give them time to grapple with their feelings and get over the shock. Don't take to heart anything they may say at first because they may just react before they have time to think things through.
All you can do is sit down with them and come out and tell them. Be honest. Be calm. Tell them you would never want to hurt them but this is what it is and that you really need their support more now than ever. Again, give them time to come to grips with the news and their feelings. Maybe even give them a few days, or a few weeks, depending on how long it takes for the shock to wear off. Just tell them what you know and then give them time to soak it all in. They will come around eventually, hopefully sooner than later.
You do need to see a doctor and get on some prenatal vitamins. If you're not covered under your parents insurance then you will also need to look into signing up for Medicaid, at least for the baby because the baby probably wouldn't be covered under your parents insurance.
Show your parents that you will take responsibility by acting responsible. Finish school, work part time (as much as you can while still doing school) and save as much as you can towards what you will need for the baby. Make sure you eat healthy, drink plenty of water, get rest and take your vitamins.
You will need to talk to the father about child support. Is he an adult? If he's your age you probably should talk to him, then your parents, then set up a meeting to meet with all of you including his parents because they would probably have to help with the support until he's able.
I know everyone will be shocked but if they love you, as I'm sure they do, they will eventually come around.
My 17 year old daughter recently told me she's pregnant too. I felt all those range of emotions at first too, including grief for her having to grow up and not be able to be as free as a child. It probably took me a good month for the shock to start to wear off and reality to sink in. I am supporting my daughter and will support her the best that I can. All we can do is take this one step at a time, one day at a time.
The hardest part is telling them but it needs to be done. I wish you well. God bless!