I had protected sex with condom and had my period three days after it (28/1/18). im now 3 days late for my period. my vagina is dry and discharged very little clear watery vaginal discharge. ive been getting cramps and constipation. could i be preg?

Yes: While it would be unlikely to get pregnant right before your period, the bleeding you initially experienced could have been implantation bleeding. It would be a good idea to do a pregnancy test and consider seeing a doctor

Pregnancy test: Agree with Dr. Reynoso. Conception, as defined by the generation of a fertilized ovum, occurs within day or so of the sex. However, it takes about 3 weeks for the embryo to make enough HCG to produce a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Practice safe sex, if you have sex. Get HPV vaccine