i am 18 need help badly..no1 to turn to

first of all, u need to turn to ur family. they would be the ones who can really take care of u.
if u dont have that option, try to seek help in 家計會, here is their website:
http://www.famplan.org.hk/
so ur planning to have ur baby, right? its not necessary to book hospital, but if you like to have ur baby in some private hospitals, then u might wanna check on their vacancy and price.
if u wanna get ur check up cheap then just go to any public hospital, they shouldnt charge you too much.

您而家已有咗4固月, 要快d去健康院登記啦
您要先到私家診所驗孕&問醫生攞張懷孕証明, 攞張懷孕証明去就近的健康院登記就可以, 但每間健康院都有固定星期幾收新症, 唔想白行一次就要先check下佢邊日收新症(http://www.fhs.gov.hk/tc_chi/centre_det/maternal/maternal.html), 登記咗之後政府醫院就會有您個record, 咁您按姑娘指示定期check-up就ok

健康院做產前檢查係唔收費的, 不過感覺上求其d, 您都可以問下就近有婦產科的醫院會唔會直接收case(有d醫院會叫您先去健康院, 由健康院transfer) 但有d就可以直接登記
醫院至少多d設備, 健康院連照超聲波的儀器都冇架...

我自己就直接去廣華登記, 亦會係廣華生(而家25週) (不過廣華已唔收明年六月預產期的新症, 如果您係哩區的就要去qe), 同時我會私家&政府2邊睇, 有d檢查政府唔會幫我做, 咁就會係私家做囉, 您而家4個月即16週, 已經miss咗check唐氏綜合症(oscar)個週數係11-13週, 不過您得18是低危一族

18-22週要做結構檢查, 您嗱嗱聲去政府登記, 如果佢排唔到期幫您做就要自己去私家做大約千幾蚊, 不過我覺得哩個檢查都幾緊要, 因為可以check清楚bb主要器官的生長情況...如有先天性缺憾(touch-wood咁講), 都可以早發現

Go to one of the private clinic for advices first (close to your appartment). At least, the doctor could give you the basic idea for you & your baby.

*** 叫醫生寫紙轉介到公立醫院

Well, first of all, I need to know why you haven't gone anywhere to do check ups up to now!!!
You're already 4 months pregnant, ur fetus has already become a BABY!!!
The most important thing for you to do now is to go to some kind of public health bureau in ur place to do monthly check ups, this is very important because they'll tell you exactly what to do! such as checking if ur capable to have a baby, is ur baby growing healthy, what you can eat and cannot eat, pills/vitamins that are good for pregnant women...etc. Public health bureau belongs to the government, so you don't have to pay. You don't need to make any advanced booking in the hospital because the health center will do that for you( but of course,you need to pay for the hospital fees, how much exactly, I don't remember, every hospital varies anyway)
I don't understand why you have no one to talk to, being pregnant is a two people thing, you cannot do all that on ur own, you should discuss it with ur other half~
Being a mother is a job that works 24hrs per day, 7days per week, and 365 days per year, I hope ur ready for it! This is hard, but it's not immpossible!
I give you all my wishes and hope you all the best!