worried I'm late into a pregnancy I didn't know about.

My wife and I tried a home inseminatin in late July. With high hopes we tested many times but all of the tests came back negative. We just assumed it didn't take. However now I'm experiencing symptoms I had in my first pregnancy. My nipples are very sore on and off. I'm producing colostrum again. I've been extremely tired lately etc. I'm worried I may be far along with a baby I didn't know about. However I haven't gotten bigger and I've Bly gained about ten pounds. Is there anyone who could help. I would like to take a blood test but I'm worried I'm wasting money.