Assalamu Alaikum Wa Rahmatullah
my husband said I gave you first divorce and went away from home I am 4 months pregnant. Please tell me whether I have been divorced or there is a possibility for rajjuu and how much time we both have for rajjuu.
بسم الله الرحمن الرحيم
In the name of Allah, the Most Gracious, the Most Merciful.
Your husband has given you the first divorce which counts as a Talaaq Raji’ (revocable divorce). 
This means that there is still the possibility of taking you back before the ending of your iddah period. The iddah of a pregnant woman ends with the birth of her child. 
After the ending of the iddah if you both decide to reconcile, then a new marriage contract and dowry will be required.
Only Allah SWT alone knows best.
Written by Aalimah Nasima Umm Hamza
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Mukhtasar al-Qudoori, Kitab at-Talaaq, page 411, (TaHa Publications)
 Mukhtasar al-Qudoori, Kitab al-Iddah, page 453, (TaHa Publications)