what should i do?

i think i’m pregnant! i have only been with my bf for about 8 months, i already have another child from a previous relationship i didnt find out i was pregnant last time until i was 16wks and i still had my period the whole way through my pregnancy, and im now showing all the signs, feeling tired- run down, frequent need to use the loo achy boobs and i have put on so much weight on my stomach feels really swollen i haven’t missed a period but they have been very light. im quite scaired 2 do a test incase it comes bak pos coz i know i wont be able 2 have a termination but i became very ill during my last pregnancy and almost lost my unborn baby i was told if i have another the same thing could happen, i dont know what to do my boyf seems ok with whatever the outcome bt he already has 2 children from dif women and is alot older than me im not sure he would stick around :unsure: