Could I be pregnant again already!?

Je
So I'm a little concerned. I just had a baby the past July, she will be 7months February 26. I have been wanting a baby for so long so I was so excited to have her. 
Well the past 3 weeks I have been having headaches, feeling dizzy, lightheaded, weak, fatigued, nauseous and moody. I just started feeling like this after my last period. I'm not scheduled to start again till another 2weeks so I haven't taken a test yet, I wanted to wait and see if I miss my period first. But was wondering if this has happened to anyone else and what yaws results were. I want another baby but Idk if i can handle it.