Should I get an abortion

SORRY FOR THE LONG POST BUT THERES LORS OF DETAILS So I had a miscarriage at 16 weeks about a year and a half ago with my ex boyfriend, we broke up soon after. In January of this year I met someone new , we have always spoken anout babies and stuff so we've always known it what we want eventually. Recently I've been getting upset because my mum is seriously ill and no medicines seem to be working so im scared she'll die and wont get to meet/wont get long with her grandchildren; I was also crying about the baby I lost. Apparently this subconsciously made my boyfriend think it would be a good idea to try for a baby (baring in mind we both live at home in very small houses/I just left my job to focus on finishing my degree/he works agency so doesn't get paid in the school holidays/ we are both applying to do our pgces in September ). I said is are you sure this is what you want, how will we afford it, where will we live and he had an answer for everything so we went ahead. last weekend we did some early pregnancy test that came back negative but my period didnt come when it was due so we suspected I was. pregnant. he then told me he doesn't want it and he wants me to have an abortion, knowing full well that,I am although pro-choice, that's not something I ever want to do. last night i found out I am 4+5 weeks and I dont know what to do!! Financially its bad timing but for my family it could be great but I don't want my boyfriend to resent me or my family but I think he was very unfair. Any advice will be greatly appreciated xxx