I dont know how things work where you are,but here,if you have a postive HPT and then you start to bleed,you can go straight to the ER and they will give you an ultra sound (vaginal if you are only a few weeks along) and they will find out whats going on.
With my son,I had only just found out I was pregnant and hadent even had my first unltra sound or seen a doctor yet and I spotted a little (just dark yellowish CM).I hadent seen a doctor of any kind yet (I hadent had the time) but I went straight to the ER and they were great.They ran blood tests and made sure everything was going fine etc...(which is was,I found out I was 11 weeks along!!

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Thats deffinately what id do if you can where you are.You dont have to be heavily pregnant for a doctor to take you seriously,if you are worried,go to the ER,explain whats happened and Im sure they will see you..I doubt they will send you home and tell you to wait.
If you have to stretch the truth a little to get them to see you (like saying you are still spotting a little etc) then do so...I have done that lots of times (our medical care here is free though).Its worth it if you go home feeling releaved