Starting to get upset

We really want to have a baby before the year is over. Our daughter just turned 3 and we never wanted them this far apart never mind 4+- years. I have been asked probably 10x this week when we are having another baby. My SIL is pregnant with her 3rd after 11 years of not wanting anymore kids. I have been having issues with af since I would say November. Had blood work done this week and it was all normal. I haven't started af this month and spotted light pink 1x a day for 2 weeks in February. All urine tests are negative blood test negative. .my doctor said to wait 2-3 months to see if af comes and if it hasn't and still negative tests to call back. I'm getting super upset and discouraged because I really want another baby and its feeling like it isnt going to happen