Trying to conceive

We want to have our 4th and last baby already our youngest is 2 and half but we want all our kids close in age , after this we are done. But I am scared for being pregnant and having to care for 3 children . If anyone has 4 kids any tips on how to handle it being pregnant and having 3 kids to care for . Or morning sickness tips so I can feel as good as I possibly can ?