TTC and work

My hubby and I do construction (yes I do every thing that he dose) we do every thing from cleaning to Billding houses. We have been trying for baby # 1 for a year and I had a CP or MC at the begging of the year. It's really hard because I don't get a BFP till I'm about two months that's how it has been in the past and I am afraid to work to hard some times if there is a chance I could be pregnant and I can't realy talk to my hubby about it because I don't want to get exited if I'm not pregnant. Can doing hard work in the beginning hurt any thing?