Late period negative tests

Soooo I'm probably going to sound stupid because I haven't really been keeping track of my cycle. I've been going off of when my mom has hers. Lol. I've only had 3 periods since my son was born but they were very regualr and on time. My mom and I have either started our periods at the same time or I start a couple of days after her. She just got off of hers yesterday so I figure mine is late. I've been taking tests because about 2 weeks ago, my fiance and I got pretty close with the pulling out and I knew a little got inside of me. I knew I'd be this way when it happened 2 weeks ago lol.

I keep saying my son (10 months) is too young (for my comfort) to be a big brother but i keep getting negative tests and it makes me sad. I guess I want another baby now deep down but I was really trying to wait until he was closer to 2. Debating on starting TTC for baby #2 now or later lol. My brother and I are 16 months apart so my mom is all for it and so is my fiance. Just makes me a little nervous lol. Is it too early to be testing maybe? I got a faint positive with my son at 3 weeks and 4 days.

Sorry for the venting/rambling, I have no friends lol