Pregnant and partners left me

Not really sure why I’m posting this here more just venting I guess . I have a 4 yo ds who starts school September and have just found out I’m 6 weeks pregnant after trying for baby #2 with my partner for 18 months. We’ve been through 4 miscarriages in the last 18 months and finally have got help with this pregnancy to see if it progresses. My partners come home tonight and told me he doesn’t love me no more and has walked out on us. This isn’t the 1st time he’s done this he did this back in February aswell which I later found out was due to him being in lots of debt because he had a problem with drink and cocaine. He promised he’d sort himself out for me and his son and begged me to continue ttc baby #2 with him. I don’t know what to think or say I’m so embarrassed I’ve given him a chance to make things better and hes done this. I can’t see a light at the end of the tunnel and the thought of bringing another baby into the world while having a 4 year old aswell and working self employed is eating away at me 😩 he left me alone my whole pregnancy with my son because he was drinking all the time and being a dick I can’t believe I was stupid enough to think he’d actually changed enough to not do it a second time round 😭😞