Advice

Hi I just wanted a little advice I’m 21 and just found out I’m pregnant with my fourth child my oldest is three my second little girl is 2 and my third little girl is 8 months nearly I’m around 7/8 weeks pregnant how does people who have had four children cope I thought I was finished having children after my last I was in the injection. My third little girl is a lot of work a lot harder than my first two I feel like I haven’t even adjusted to her? She barely sleeps at night maybe 2/3 hours max she constantly wants attention or she screams I can’t put her down I barely function as it with her I just can’t imagine how I’m going to cope with another any friendly advice thanks in advance