how to check your cervix for pregnancy

3 months pp and I've been getting cramps on and off kinda makes me feel a little nauseas when I get them it honestly feels like implatantion I felt like this with my son Anywasys my question is I did a urine test Tuesday for an X-ray and was negative let alone I had this little pains already and Friday I did a home one negative and this Monday I went to my ob and asked if I didn't mind doing a blood test one and also send me for an ultrasound transvagibal just to check if something is going on ... Could all this test from urine be wrong ? I tested positive 2 days after my missed period with my son 😁 I even get leg cramps  I tried checking my cervix and it feels up high and no openening is felt ... I do have some discharge as well like clear white yellow idk how to explain it no foul smell or anything tough I'm also a little bloated and gassy when I get this pains we've been using condoms and also he did put it twice and got out when we didn't use condoms but it would be a stroke or two ... Or we just fore play he did jack off once to finish of and shoot right next to my vagina but nothing got in