Feeling alone w/so many problems! Help!!

Grim • I love being a phenomenal mommy ! <3 I am 20yrs old and I love my babies !(;
So I am 7.5 months pregnant,30weeks & I have been feeling alone and just out of energy. I have a 8 month old boy as well. I do the cooking, cleaning, & i do all of the taking care of my son. In between those I have also been dealing with round ligament pain (RLP)and headaches from time to time but more of the RLP. I even at times have to take out the trash with my son on my hip and walk down a bunch of steep stairs, cause I stay upstairs in a apt. I sat here and also do everything for my fiancé ,find his clothes, iron them, cook,clean, the whole 9yards and when I want a break I can't he complains and says he's leaving me and says I do a lot but all he does is work. Just recently he just lost his job but has a back up job but hasent started he still waiting for the place to call him for orientation . But on the side of that he goes to the plasma every 2/5days&walks because we don't have transportation yet. But when he is at the plasma he goes by his brother house play video games . I don't think it's fair because he has all this free time now and not once has he asked if I need help with anything. Not to mention I get up atleast 3/4times at night just to fix him food. Not to also mention if I'm to tired to give him sex he says I'm not on my job and that he's leaving... I need advice!! How do I not put so much stress on myself or beat myself up about the harsh and mean things he say towards me?? & I'm not the one to argue cause I hate it and it's pointless.