Is it possible

So 3 days ago I was still on my period with medium flow and my bf and I had sex... Withdrawal never got me pregnant and the day after also sex on my period with light flow and also withdrawal.. It's 3 days after the first unprotected interaction and I did a baking soda test with an afternoon test aand it fizzed.. My period ended yesterday and I've eaten a lot today. . Could I be pregnant, please if there are any doctors I would really appreciate it