Is there any chance?

[ItsTime]

Hello, this is my first time here and I would appreciate some comments/thoughts on do I have a chance for being pregnant. I have read tons of web pages and I am confused. I have from 29 to 32 long cycle. The last time we had sex was June 30th and I was expecting to get my period within a day or two. From July 10th to today, I am experiencing nipple pain (it does not last for whole day, only short time), headache, nausea (especially in the morning when I wake up and last day I was on a bus driving to work, but I did not throw up), lower back pain, sometimes I have a feeling like somebody would stab me into my lower part of stomach and usually through a day I have a balloon in my belly (its is noticeable since I am skinny). The blowing disappears next day. I am expecting to get my next period around July 30th.
Based on the fact above, is there a chance I got pregnant? What puzzles me is that sex occurred right before period (which was really light and did not last long). I am not sure when my ovulation is.
Thank you in advance for all replies.

 

[scn]

If you're not due your period until 30th July you're probably in your fertile week?

 

[ItsTime]

Well, yeah. I think so too, but since my period are from 29 to 32 (sometimes even 36) days, I am not sure when my ovulation time is. These days I have a feeling like my body is playing games with me. All these symptoms I am having... does not make sense