Advice please

Courtney
I know this seems crazy but I've been using the maybe baby ovulation kit and it said I ovulated 4 days ago . This morning I was awoken at 4am with a really weird dream , almost a nightmare & now I have some very mild cramping . How early can you start to feel pregnancy symptoms ?
We have been TTC for 3 years now however in year 2 my husband was diagnosed with cancer - he is in the clear now and sperm count is up so really praying for a miracle this month !