Am i just going through a clucky stage?

I am so sorry if i have put this in the wrong section...im not sure where to put it. I am already blessed with 3 children and i feel so incredibly selfish that i have a slight desire to add one more to our family.

Hubby was only given a 1% chance of ever having kids naturally due to mobility and morphology issues with his sperm. We were successful through IVF/ICSI with our first. 2 years later i discovered i was pregnant naturally with our 2nd child ....and 3 months after giving birth to my 2nd, i discovered i was once again pregnant naturally with our third.

I swore i never wanted anymore kids as im sooo busy with the 3 i have and i also work part time. Im tired, exhausted and i love it when i get the opportunity to have time to myself. So i cannot wait till my youngest 2 are in school lol.

It seems really impractical to add another one. Our house is not big enough and we would have to upgrade both cars, but lately I've been urging to want another baby and this feeling isnt going away.

I was a little disappointed to see a BFN on my hpt this morning and this has got me thinking even more...

Any advice?