Pregnant or not pregnant? That's the question.

Well I might just be wishful thinking, but I THINK I might be pregnant. I have 3 kids, two from a 6 year relationship, and one from another 5 year relationship, so I know what it's like to be pregnant before. With them though I had implantation bleeding and all the classic pregnancy symptoms, so it was not a surprise really. My last period was 01/28 and I was due for one on 02/22. Normally Aunt Flo comes like clockwork and the only times in my life I was late was when I was pregnant. I've been married to my husband for a little over a year now and we've been actively trying without any success, ovulation tests, negative hpts... He doesn't have any kids and this would be his first. I haven't had any signs that Aunt Flo is coming, normally I have a good case of being crabby, my back hurts and I can only sleep on my stomach, but none of that going on here. Since I'm going on 4 days late, I'm going to buy a pregnancy test when I go out again or have my husband pick one up, but I want to surprise him so I think I'll just try to do it, that opportunity won't come til Friday though, so I'm in waiting until then. I'll update when I find out what's going on. Hoping I'm pregnant because my husband will be thrilled, but as this would be number 4 for me, and the first 3 weren't easy at all, I don't know how my body will take it.But for right now it's the waiting game, so I guess only time will tell.