Tigthness In stomach After I Masturbate

Ok So Idk If I’m Pregnant Yet I Had A Light Period On sept 7-11 The Beginning Of The Month Only last 5 days when it usually last 7 I’ve been throwing up sore breast stomach been going ape shit a lot of symptoms but Everytime I Test I get an negative my next period due in 12 days then I just recently masturbated with a toy and when I climax my stomach wouldn’t go in all the way idk how to explain it like it was a lil tight. Did any woman pregnant experience this?