4 DPO feel SHIT! Plus another positive opk?

So I got my ewcm Tuesday & Wednesday did the deed on Wednesday and only Wednesday ( I have a 10 month old who likes to be a bit of a cock block 😂) and then today I feel shocking I’m soo tired And i have a horrible headache so I decided to do an opk just now (because why not) and it was super positive! I remember the night before I got my bfp with my son I got a super positive opk too but that was the day before AF was due! This is only 4dpo? Do you think I could be pregnant again?

I’ve also got like a heavy feeling that keeps coming in waves in my stomach 🤷🏼‍♀️