To test or not to test? 🤔

I just recently had my first child. She was born August 14th and since my 6 week mark, my husband and I have been having sex A LOT unprotected and he’s came inside of me every time. I’m 10 weeks pp. and I’m also breastfeeding which I hear makes you very fertile & haven’t had my period yet! We really want our children to be close in age and to grow up together. I’m 8 years older than my sister. And he’s 12 years older than his sister. For the last two weeks I’ve been feeling extremely dizzy and have been having a bunch of headaches. With a little nausea. I kind of want to take a test but don’t know if it may be too soon or not. Any ideas? 😬😜