Hi doc,
I am 27yrs old and have been getting my periods regularly. My usual date is 3rd or 4th of every month. I got my periods on 3rd may and was sexually active with my partner on 18th may. Since he ejaculated inside me so I took an I-pill within 18hrs of the act. I got my periods on 4th of June and they lasted for 5days but yes I am doubtful whether it was menses or just spotting because I get heavy periods and this time they were within normal limits. Fortunately I didn't experience any discomfort which is quite unsual for me because I face severe cramps and tenderness in breasts which all was amiss. Its already 5th July and I have not got my periods yet though I have not been involved sexually during this period. I am worried whether that bleeding was proper menses or spotting... am I pregnant?

Any time there is penile insertion there is the risk of pregnancy. You can reduce the risk, but not eliminate it.

So it is possible. You will have to wait another 2 weeks to take a pregnancy test.

Since there was penile insertion as noted, of course you could be. At this point a HPT, (test) could be done to find out, always use first urine of the morning.

But I am sure you are aware by reading the instructions with the pills, that the I pill (morning after pill) will stop you from having periods sometimes, make periods late and more.
So this could be one of the many side effects of the pill also

But as stated I did have menses on 4th June which lasted up to 5days. But I am unsure whether to term them as proper menses or just another form of spotting. I was not involved with my partner after 18th may. So I am very confused. To add, I have been working out rigourously in the gym and taking black coffee in the morning for more than 10days now.

It's been answered... if you are still concerned, take a test. There is no way for us to really know for sure so the only choice you have now is to wait longer and see what happens or take a test.