I Have Always Passed Out After Giving Blood Or Getting

I have always passed out after giving blood or getting my blood drawn. I’m not scared of needles, it’s just something I do with no real reason behind it (that I know of). About four months ago (I was on my period), I woke up with massive stomach pains and felt like I had to use the bathroom and/or puke, after going to the bathroom, I passed out. Fast forward to tonight, on my period again, I had the same stomach pains that caused me to once again pass out. I am not sure if there is a connection with blood loss or not but I am starting to worry. Any help?